Table expressions

Tables are one of the core data structures in Ibis.

Table

Table(self, arg)

An immutable and lazy dataframe.

Analogous to a SQL table or a pandas DataFrame. A table expression contains an ordered set of named columns, each with a single known type. Unless explicitly ordered with an .order_by(), the order of rows is undefined.

Table immutability means that the data underlying an Ibis Table cannot be modified: every method on a Table returns a new Table with those changes. Laziness means that an Ibis Table expression does not run your computation every time you call one of its methods. Instead, it is a symbolic expression that represents a set of operations to be performed, which typically is translated into a SQL query. That SQL query is then executed on a backend, where the data actually lives. The result (now small enough to be manageable) can then be materialized back into python as a pandas/pyarrow/python DataFrame/Column/scalar.

You will not create Table objects directly. Instead, you will create one

from a pandas DataFrame, pyarrow table, Polars table, or raw python dicts/lists with ibis.memtable(df)
from an existing table in a data platform with connection.table("name")
from a file or URL, into a specific backend with connection.read_csv/parquet/json("path/to/file") (only some backends, typically local ones, support this)
from a file or URL, into the default backend with ibis.read_csv/read_json/read_parquet("path/to/file")

See the user guide for more info.

Attributes

Name	Description
columns	Return a `tuple` of column names in this table.

Methods

Name	Description
aggregate	Aggregate a table with a given set of reductions grouping by `by`.
alias	Create a table expression with a specific name `alias`.
as_scalar	Inform ibis that the table expression should be treated as a scalar.
as_table	Promote the expression to a table.
asof_join	Perform an “as-of” join between `left` and `right`.
bind	Bind column values to a table expression.
cache	Cache the provided expression.
cast	Cast the columns of a table.
compile	Compile to an execution target.
count	Compute the number of rows in the table.
cross_join	Compute the cross join of a sequence of tables.
describe	Return summary information about a table.
difference	Compute the set difference of multiple table expressions.
distinct	Return a Table with duplicate rows removed.
drop	Remove fields from a table.
drop_null	Remove rows with null values from the table.
dropna	Deprecated - use `drop_null` instead.
equals	Return whether this expression is structurally equivalent to `other`.
execute	Execute an expression against its backend if one exists.
fill_null	Fill null values in a table expression.
fillna	Deprecated - use `fill_null` instead.
filter	Select rows from `table` based on `predicates`.
get_backend	Get the current Ibis backend of the expression.
get_name	Return the fully qualified name of the table.
group_by	Create a grouped table expression.
head	Select the first `n` rows of a table.
info	Return summary information about a table.
intersect	Compute the set intersection of multiple table expressions.
join	Perform a join between two tables.
limit	Select `n` rows from `self` starting at `offset`.
mutate	Add columns to a table expression.
nunique	Compute the number of unique rows in the table.
order_by	Sort a table by one or more expressions.
pipe	Compose `f` with `self`.
pivot_longer	Transform a table from wider to longer.
pivot_wider	Pivot a table to a wider format.
preview	Return a subset as a Rich Table.
relabel	Deprecated in favor of `Table.rename`.
relocate	Relocate `columns` before or after other specified columns.
rename	Rename columns in the table.
rowid	A unique integer per row.
sample	Sample a fraction of rows from a table.
schema	Return the Schema for this table.
select	Compute a new table expression using `exprs` and `named_exprs`.
sql	Run a SQL query against a table expression.
to_array	Deprecated - use `as_scalar` instead.
to_csv	Write the results of executing the given expression to a CSV file.
to_delta	Write the results of executing the given expression to a Delta Lake table.
to_pandas	Convert a table expression to a pandas DataFrame.
to_pandas_batches	Execute expression and return an iterator of pandas DataFrames.
to_parquet	Write the results of executing the given expression to a parquet file.
to_parquet_dir	Write the results of executing the given expression to a parquet file in a directory.
to_polars	Execute expression and return results as a polars dataframe.
to_pyarrow	Execute expression and return results in as a pyarrow table.
to_pyarrow_batches	Execute expression and return a RecordBatchReader.
to_torch	Execute an expression and return results as a dictionary of torch tensors.
try_cast	Cast the columns of a table.
unbind	Return an expression built on `UnboundTable` instead of backend-specific objects.
union	Compute the set union of multiple table expressions.
unnest	Unnest an array `column` from a table.
unpack	Project the struct fields of each of `columns` into `self`.
value_counts	Compute a frequency table of this table’s values.
view	Create a new table expression distinct from the current one.
visualize	Visualize an expression as a GraphViz graph in the browser.

aggregate

aggregate(metrics=(), by=(), having=(), **kwargs)

Aggregate a table with a given set of reductions grouping by by.

Parameters

Name	Type	Description	Default
metrics	Sequence[`ir`.`Scalar`] \| None	Aggregate expressions. These can be any scalar-producing expression, including aggregation functions like `sum` or literal values like `ibis.literal(1)`.	`()`
by	Sequence[`ir`.`Value`] \| None	Grouping expressions.	`()`
having	Sequence[`ir`.`BooleanValue`] \| None	Post-aggregation filters. The shape requirements are the same `metrics`, but the output type for `having` is `boolean`. ::: {.callout-warning} ## Expressions like `x is None` return `bool` and will not generate a SQL comparison to `NULL` :::	`()`
kwargs	`ir`.`Value`	Named aggregate expressions	`{}`

Returns

Name	Type	Description
	Table	An aggregate table expression

Examples

>>> import ibis
>>> from ibis import _
>>> ibis.options.interactive = True
>>> t = ibis.memtable(
...     {
...         "fruit": ["apple", "apple", "banana", "orange"],
...         "price": [0.5, 0.5, 0.25, 0.33],
...     }
... )
>>> t

┏━━━━━━━━┳━━━━━━━━━┓
┃ fruit  ┃ price   ┃
┡━━━━━━━━╇━━━━━━━━━┩
│ string │ float64 │
├────────┼─────────┤
│ apple  │    0.50 │
│ apple  │    0.50 │
│ banana │    0.25 │
│ orange │    0.33 │
└────────┴─────────┘

>>> t.aggregate(
...     by=["fruit"],
...     total_cost=_.price.sum(),
...     avg_cost=_.price.mean(),
...     having=_.price.sum() < 0.5,
... )

┏━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━┓
┃ fruit  ┃ total_cost ┃ avg_cost ┃
┡━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━┩
│ string │ float64    │ float64  │
├────────┼────────────┼──────────┤
│ banana │       0.25 │     0.25 │
│ orange │       0.33 │     0.33 │
└────────┴────────────┴──────────┘

alias

alias(alias)

Create a table expression with a specific name alias.

This method is useful for exposing an ibis expression to the underlying backend for use in the Table.sql method.

.alias will create a temporary view

.alias creates a temporary view in the database.

This side effect will be removed in a future version of ibis and is not part of the public API.

Parameters

Name	Type	Description	Default
alias	str	Name of the child expression	required

Returns

Name	Type	Description
	Table	An table expression

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> expr = t.alias("pingüinos").sql('SELECT * FROM "pingüinos" LIMIT 5')
>>> expr

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
│ Adelie  │ Torgersen │           NULL │          NULL │              NULL │        NULL │ NULL   │  2007 │
│ Adelie  │ Torgersen │           36.7 │          19.3 │               193 │        3450 │ female │  2007 │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

as_scalar

as_scalar()

Inform ibis that the table expression should be treated as a scalar.

Note that the table must have exactly one column and one row for this to work. If the table has more than one column an error will be raised in expression construction time. If the table has more than one row an error will be raised by the backend when the expression is executed.

Returns

Name	Type	Description
	`Scalar`	A scalar subquery

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> heavy_gentoo = t.filter(t.species == "Gentoo", t.body_mass_g > 6200)
>>> from_that_island = t.filter(t.island == heavy_gentoo.select("island").as_scalar())
>>> from_that_island.species.value_counts().order_by("species")

┏━━━━━━━━━┳━━━━━━━━━━━━━━━┓
┃ species ┃ species_count ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━━━┩
│ string  │ int64         │
├─────────┼───────────────┤
│ Adelie  │            44 │
│ Gentoo  │           124 │
└─────────┴───────────────┘

as_table

as_table()

Promote the expression to a table.

This method is a no-op for table expressions.

Returns

Name	Type	Description
	Table	A table expression

Examples

>>> t = ibis.table(dict(a="int"), name="t")
>>> s = t.as_table()
>>> t is s

True

asof_join

asof_join(
    left,
    right,
    on,
    predicates=(),
    tolerance=None,
    *,
    lname='',
    rname='{name}_right',
)

Perform an “as-of” join between left and right.

Similar to a left join except that the match is done on nearest key rather than equal keys.

Parameters

Name	Type	Description	Default
left	Table	Table expression	required
right	Table	Table expression	required
on	str \| `ir`.`BooleanColumn`	Closest match inequality condition	required
predicates	str \| `ir`.`Column` \| Sequence[str \| `ir`.`Column`]	Additional join predicates	`()`
tolerance	str \| `ir`.`IntervalScalar` \| None	Amount of time to look behind when joining	`None`
lname	str	A format string to use to rename overlapping columns in the left table (e.g. `"left_{name}"`).	`''`
rname	str	A format string to use to rename overlapping columns in the right table (e.g. `"right_{name}"`).	`'{name}_right'`

Returns

Name	Type	Description
	Table	Table expression

Examples

>>> from datetime import datetime, timedelta
>>> import ibis
>>> ibis.options.interactive = True
>>> sensors = ibis.memtable(
...     {
...         "site": ["a", "b", "a", "b", "a"],
...         "humidity": [0.3, 0.4, 0.5, 0.6, 0.7],
...         "event_time": [
...             datetime(2024, 11, 16, 12, 0, 15, 500000),
...             datetime(2024, 11, 16, 12, 0, 15, 700000),
...             datetime(2024, 11, 17, 18, 12, 14, 950000),
...             datetime(2024, 11, 17, 18, 12, 15, 120000),
...             datetime(2024, 11, 18, 18, 12, 15, 100000),
...         ],
...     }
... )
>>> events = ibis.memtable(
...     {
...         "site": ["a", "b", "a"],
...         "event_type": [
...             "cloud coverage",
...             "rain start",
...             "rain stop",
...         ],
...         "event_time": [
...             datetime(2024, 11, 16, 12, 0, 15, 400000),
...             datetime(2024, 11, 17, 18, 12, 15, 100000),
...             datetime(2024, 11, 18, 18, 12, 15, 100000),
...         ],
...     }
... )

This setup simulates time-series data by pairing irregularly collected sensor readings with weather events, enabling analysis of environmental conditions before each event. We will use the asof_join method to match each event with the most recent prior sensor reading from the sensors table at the same site.

>>> sensors

┏━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ site   ┃ humidity ┃ event_time              ┃
┡━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ string │ float64  │ timestamp               │
├────────┼──────────┼─────────────────────────┤
│ a      │      0.3 │ 2024-11-16 12:00:15.500 │
│ b      │      0.4 │ 2024-11-16 12:00:15.700 │
│ a      │      0.5 │ 2024-11-17 18:12:14.950 │
│ b      │      0.6 │ 2024-11-17 18:12:15.120 │
│ a      │      0.7 │ 2024-11-18 18:12:15.100 │
└────────┴──────────┴─────────────────────────┘

>>> events

┏━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ site   ┃ event_type     ┃ event_time              ┃
┡━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ string │ string         │ timestamp               │
├────────┼────────────────┼─────────────────────────┤
│ a      │ cloud coverage │ 2024-11-16 12:00:15.400 │
│ b      │ rain start     │ 2024-11-17 18:12:15.100 │
│ a      │ rain stop      │ 2024-11-18 18:12:15.100 │
└────────┴────────────────┴─────────────────────────┘

We can find the closest event to each sensor reading with a 1 second tolerance. Using the “site” column as a join predicate ensures we only match events that occurred at or near the same site as the sensor reading.

>>> tolerance = timedelta(seconds=1)
>>> sensors.asof_join(events, on="event_time", predicates="site", tolerance=tolerance).drop(
...     "event_time_right"
... ).order_by("event_time")

┏━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓
┃ site   ┃ humidity ┃ event_time              ┃ site_right ┃ event_type     ┃
┡━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━┩
│ string │ float64  │ timestamp               │ string     │ string         │
├────────┼──────────┼─────────────────────────┼────────────┼────────────────┤
│ a      │      0.3 │ 2024-11-16 12:00:15.500 │ a          │ cloud coverage │
│ b      │      0.4 │ 2024-11-16 12:00:15.700 │ NULL       │ NULL           │
│ a      │      0.5 │ 2024-11-17 18:12:14.950 │ NULL       │ NULL           │
│ b      │      0.6 │ 2024-11-17 18:12:15.120 │ b          │ rain start     │
│ a      │      0.7 │ 2024-11-18 18:12:15.100 │ a          │ rain stop      │
└────────┴──────────┴─────────────────────────┴────────────┴────────────────┘

bind

bind(*args, **kwargs)

Bind column values to a table expression.

This method handles the binding of every kind of column-like value that Ibis handles, including strings, integers, deferred expressions and selectors, to a table expression.

Parameters

Name	Type	Description	Default
args	Any	Column-like values to bind.	`()`
kwargs	Any	Column-like values to bind, with names.	`{}`

Returns

Name	Type	Description
	tuple[Value, …]	A tuple of bound values

cache

cache()

Cache the provided expression.

All subsequent operations on the returned expression will be performed on the cached data. The lifetime of the cached table is tied to its python references (ie. it is released once the last reference to it is garbage collected). Alternatively, use the with statement or call the .release() method for more control.

This method is idempotent: calling it multiple times in succession will return the same value as the first call.

This method eagerly evaluates the expression prior to caching

Subsequent evaluations will not recompute the expression so method chaining will not incur the overhead of caching more than once.

Returns

Name	Type	Description
	Table	Cached table

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> heavy_computation = ibis.literal("Heavy Computation")
>>> cached_penguins = t.mutate(computation=heavy_computation).cache()
>>> cached_penguins

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃ computation       ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │ string            │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┼───────────────────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │ Heavy Computation │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │ Heavy Computation │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │ Heavy Computation │
│ Adelie  │ Torgersen │           NULL │          NULL │              NULL │        NULL │ NULL   │  2007 │ Heavy Computation │
│ Adelie  │ Torgersen │           36.7 │          19.3 │               193 │        3450 │ female │  2007 │ Heavy Computation │
│ Adelie  │ Torgersen │           39.3 │          20.6 │               190 │        3650 │ male   │  2007 │ Heavy Computation │
│ Adelie  │ Torgersen │           38.9 │          17.8 │               181 │        3625 │ female │  2007 │ Heavy Computation │
│ Adelie  │ Torgersen │           39.2 │          19.6 │               195 │        4675 │ male   │  2007 │ Heavy Computation │
│ Adelie  │ Torgersen │           34.1 │          18.1 │               193 │        3475 │ NULL   │  2007 │ Heavy Computation │
│ Adelie  │ Torgersen │           42.0 │          20.2 │               190 │        4250 │ NULL   │  2007 │ Heavy Computation │
│ …       │ …         │              … │             … │                 … │           … │ …      │     … │ …                 │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┴───────────────────┘

Explicit cache cleanup

>>> with t.mutate(computation=heavy_computation).cache() as cached_penguins:
...     cached_penguins

cast

cast(schema)

Cast the columns of a table.

Similar to pandas.DataFrame.astype.

If you need to cast columns to a single type, use selectors.

Parameters

Name	Type	Description	Default
schema	`SchemaLike`	Mapping, schema or iterable of pairs to use for casting	required

Returns

Name	Type	Description
	Table	Casted table

Examples

>>> import ibis
>>> import ibis.selectors as s
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> t.schema()

ibis.Schema {
  species            string
  island             string
  bill_length_mm     float64
  bill_depth_mm      float64
  flipper_length_mm  int64
  body_mass_g        int64
  sex                string
  year               int64
}

>>> cols = ["body_mass_g", "bill_length_mm"]
>>> t[cols].head()

┏━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓
┃ body_mass_g ┃ bill_length_mm ┃
┡━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━┩
│ int64       │ float64        │
├─────────────┼────────────────┤
│        3750 │           39.1 │
│        3800 │           39.5 │
│        3250 │           40.3 │
│        NULL │           NULL │
│        3450 │           36.7 │
└─────────────┴────────────────┘

Columns not present in the input schema will be passed through unchanged

>>> t.columns

('species',
 'island',
 'bill_length_mm',
 'bill_depth_mm',
 'flipper_length_mm',
 'body_mass_g',
 'sex',
 'year')

>>> expr = t.cast({"body_mass_g": "float64", "bill_length_mm": "int"})
>>> expr.select(*cols).head()

┏━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓
┃ body_mass_g ┃ bill_length_mm ┃
┡━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━┩
│ float64     │ int64          │
├─────────────┼────────────────┤
│      3750.0 │             39 │
│      3800.0 │             40 │
│      3250.0 │             40 │
│        NULL │           NULL │
│      3450.0 │             37 │
└─────────────┴────────────────┘

Columns that are in the input schema but not in the table raise an error

>>> t.cast({"foo": "string"})

---------------------------------------------------------------------------
IbisError                                 Traceback (most recent call last)
Cell In[47], line 1
----> 1 t.cast({"foo": "string"})  

File ~/work/ibis/ibis/ibis/expr/types/relations.py:447, in Table.cast(self, schema)
    372 def cast(self, schema: SchemaLike) -> Table:
    373     """Cast the columns of a table.
    374 
    375     Similar to `pandas.DataFrame.astype`.
   (...)
    445     ibis.common.exceptions.IbisError: Cast schema has fields that are not in the table: ['foo']
    446     """
--> 447     return self._cast(schema, cast_method="cast")

File ~/work/ibis/ibis/ibis/expr/types/relations.py:490, in Table._cast(self, schema, cast_method)
    488 columns = self.columns
    489 if missing_fields := frozenset(schema.names).difference(columns):
--> 490     raise com.IbisError(
    491         f"Cast schema has fields that are not in the table: {sorted(missing_fields)}"
    492     )
    494 for col in columns:
    495     if (new_type := schema.get(col)) is not None:

IbisError: Cast schema has fields that are not in the table: ['foo']

compile

compile(limit=None, params=None, pretty=False)

Compile to an execution target.

Parameters

Name	Type	Description	Default
limit	int \| None	An integer to effect a specific row limit. A value of `None` means “no limit”. The default is in `ibis/config.py`.	`None`
params	Mapping[`ir`.`Value`, Any] \| None	Mapping of scalar parameter expressions to value	`None`
pretty	bool	In case of SQL backends, return a pretty formatted SQL query.	`False`

Returns

Name	Type	Description
	str	SQL query representation of the expression

Examples

>>> import ibis
>>> d = {"a": [1, 2, 3], "b": [4, 5, 6]}
>>> con = ibis.duckdb.connect()
>>> t = con.create_table("t", d)
>>> expr = t.mutate(c=t.a + t.b)
>>> expr.compile()

'SELECT "t0"."a", "t0"."b", "t0"."a" + "t0"."b" AS "c" FROM "memory"."main"."t" AS "t0"'

If you want to see the pretty formatted SQL query, set pretty to True.

>>> expr.compile(pretty=True)

'SELECT\n  "t0"."a",\n  "t0"."b",\n  "t0"."a" + "t0"."b" AS "c"\nFROM "memory"."main"."t" AS "t0"'

If the expression does not have a backend, an error will be raised.

>>> t = ibis.memtable(d)
>>> expr = t.mutate(c=t.a + t.b)
>>> expr.compile()  # quartodoc: +EXPECTED_FAILURE

---------------------------------------------------------------------------
IbisError                                 Traceback (most recent call last)
Cell In[56], line 3
      1 t = ibis.memtable(d)
      2 expr = t.mutate(c=t.a + t.b)
----> 3 expr.compile()  # quartodoc: +EXPECTED_FAILURE

File ~/work/ibis/ibis/ibis/expr/types/core.py:506, in Expr.compile(self, limit, params, pretty)
    457 def compile(
    458     self,
    459     limit: int | None = None,
    460     params: Mapping[ir.Value, Any] | None = None,
    461     pretty: bool = False,
    462 ) -> str:
    463     r"""Compile to an execution target.
    464 
    465     Parameters
   (...)
    504     [`ibis.to_sql()`](./expression-generic.qmd#ibis.to_sql)
    505     """
--> 506     return self._find_backend().compile(
    507         self, limit=limit, params=params, pretty=pretty
    508     )

File ~/work/ibis/ibis/ibis/expr/types/core.py:368, in Expr._find_backend(self, use_default)
    366     default = _default_backend() if use_default else None
    367     if default is None:
--> 368         raise IbisError(
    369             "Expression depends on no backends, and found no default"
    370         )
    371     return default
    373 if len(backends) > 1:

IbisError: Expression depends on no backends, and found no default

count

count(where=None)

Compute the number of rows in the table.

Parameters

Name	Type	Description	Default
where	`ir`.`BooleanValue` \| None	Optional boolean expression to filter rows when counting.	`None`

Returns

Name	Type	Description
	`IntegerScalar`	Number of rows in the table

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.memtable({"a": ["foo", "bar", "baz"]})
>>> t

┏━━━━━━━━┓
┃ a      ┃
┡━━━━━━━━┩
│ string │
├────────┤
│ foo    │
│ bar    │
│ baz    │
└────────┘

>>> t.count()

┌───┐
│ 3 │
└───┘

>>> t.count(t.a != "foo")

┌───┐
│ 2 │
└───┘

>>> type(t.count())

ibis.expr.types.numeric.IntegerScalar

cross_join

cross_join(left, right, *rest, lname='', rname='{name}_right')

Compute the cross join of a sequence of tables.

Parameters

Name	Type	Description	Default
left	Table	Left table	required
right	Table	Right table	required
rest	Table	Additional tables to cross join	`()`
lname	str	A format string to use to rename overlapping columns in the left table (e.g. `"left_{name}"`).	`''`
rname	str	A format string to use to rename overlapping columns in the right table (e.g. `"right_{name}"`).	`'{name}_right'`

Returns

Name	Type	Description
	Table	Cross join of `left`, `right` and `rest`

Examples

>>> import ibis
>>> import ibis.selectors as s
>>> from ibis import _
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> t.count()

┌─────┐
│ 344 │
└─────┘

>>> agg = t.drop("year").agg(s.across(s.numeric(), _.mean()))
>>> expr = t.cross_join(agg)
>>> expr

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃ bill_length_mm_right ┃ bill_depth_mm_right ┃ flipper_length_mm_right ┃ body_mass_g_right ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │ float64              │ float64             │ float64                 │ float64           │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┼──────────────────────┼─────────────────────┼─────────────────────────┼───────────────────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │             43.92193 │            17.15117 │              200.915205 │       4201.754386 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │             43.92193 │            17.15117 │              200.915205 │       4201.754386 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │             43.92193 │            17.15117 │              200.915205 │       4201.754386 │
│ Adelie  │ Torgersen │           NULL │          NULL │              NULL │        NULL │ NULL   │  2007 │             43.92193 │            17.15117 │              200.915205 │       4201.754386 │
│ Adelie  │ Torgersen │           36.7 │          19.3 │               193 │        3450 │ female │  2007 │             43.92193 │            17.15117 │              200.915205 │       4201.754386 │
│ Adelie  │ Torgersen │           39.3 │          20.6 │               190 │        3650 │ male   │  2007 │             43.92193 │            17.15117 │              200.915205 │       4201.754386 │
│ Adelie  │ Torgersen │           38.9 │          17.8 │               181 │        3625 │ female │  2007 │             43.92193 │            17.15117 │              200.915205 │       4201.754386 │
│ Adelie  │ Torgersen │           39.2 │          19.6 │               195 │        4675 │ male   │  2007 │             43.92193 │            17.15117 │              200.915205 │       4201.754386 │
│ Adelie  │ Torgersen │           34.1 │          18.1 │               193 │        3475 │ NULL   │  2007 │             43.92193 │            17.15117 │              200.915205 │       4201.754386 │
│ Adelie  │ Torgersen │           42.0 │          20.2 │               190 │        4250 │ NULL   │  2007 │             43.92193 │            17.15117 │              200.915205 │       4201.754386 │
│ …       │ …         │              … │             … │                 … │           … │ …      │     … │                    … │                   … │                       … │                 … │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┴──────────────────────┴─────────────────────┴─────────────────────────┴───────────────────┘

>>> expr.columns

('species',
 'island',
 'bill_length_mm',
 'bill_depth_mm',
 'flipper_length_mm',
 'body_mass_g',
 'sex',
 'year',
 'bill_length_mm_right',
 'bill_depth_mm_right',
 'flipper_length_mm_right',
 'body_mass_g_right')

>>> expr.count()

┌─────┐
│ 344 │
└─────┘

describe

describe(quantile=(0.25, 0.5, 0.75))

Return summary information about a table.

Parameters

Name	Type	Description	Default
quantile	Sequence[`ir`.`NumericValue` \| float]	The quantiles to compute for numerical columns. Defaults to (0.25, 0.5, 0.75).	`(0.25, 0.5, 0.75)`

Returns

Name	Type	Description
	Table	A table containing summary information about the columns of self.

Notes

This function computes summary statistics for each column in the table. For numerical columns, it computes statistics such as minimum, maximum, mean, standard deviation, and quantiles. For string columns, it computes the mode and the number of unique values.

Examples

>>> import ibis
>>> import ibis.selectors as s
>>> ibis.options.interactive = True
>>> p = ibis.examples.penguins.fetch()
>>> p.describe()

┏━━━━━━━━━━━━━━━━━━━┳━━━━━━━┳━━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┓
┃ name              ┃ pos   ┃ type    ┃ count ┃ nulls ┃ unique ┃ mode   ┃ mean        ┃ std        ┃ min     ┃ p25      ┃ p50     ┃ p75     ┃ max     ┃
┡━━━━━━━━━━━━━━━━━━━╇━━━━━━━╇━━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━┩
│ string            │ int16 │ string  │ int64 │ int64 │ int64  │ string │ float64     │ float64    │ float64 │ float64  │ float64 │ float64 │ float64 │
├───────────────────┼───────┼─────────┼───────┼───────┼────────┼────────┼─────────────┼────────────┼─────────┼──────────┼─────────┼─────────┼─────────┤
│ species           │     0 │ string  │   344 │     0 │      3 │ Adelie │        NULL │       NULL │    NULL │     NULL │    NULL │    NULL │    NULL │
│ island            │     1 │ string  │   344 │     0 │      3 │ Biscoe │        NULL │       NULL │    NULL │     NULL │    NULL │    NULL │    NULL │
│ bill_length_mm    │     2 │ float64 │   344 │     2 │    164 │ NULL   │   43.921930 │   5.459584 │    32.1 │   39.225 │   44.45 │    48.5 │    59.6 │
│ bill_depth_mm     │     3 │ float64 │   344 │     2 │     80 │ NULL   │   17.151170 │   1.974793 │    13.1 │   15.600 │   17.30 │    18.7 │    21.5 │
│ flipper_length_mm │     4 │ int64   │   344 │     2 │     55 │ NULL   │  200.915205 │  14.061714 │   172.0 │  190.000 │  197.00 │   213.0 │   231.0 │
│ body_mass_g       │     5 │ int64   │   344 │     2 │     94 │ NULL   │ 4201.754386 │ 801.954536 │  2700.0 │ 3550.000 │ 4050.00 │  4750.0 │  6300.0 │
│ sex               │     6 │ string  │   344 │    11 │      2 │ male   │        NULL │       NULL │    NULL │     NULL │    NULL │    NULL │    NULL │
│ year              │     7 │ int64   │   344 │     0 │      3 │ NULL   │ 2008.029070 │   0.818356 │  2007.0 │ 2007.000 │ 2008.00 │  2009.0 │  2009.0 │
└───────────────────┴───────┴─────────┴───────┴───────┴────────┴────────┴─────────────┴────────────┴─────────┴──────────┴─────────┴─────────┴─────────┘

>>> p.select(s.of_type("numeric")).describe()

┏━━━━━━━━━━━━━━━━━━━┳━━━━━━━┳━━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┓
┃ name              ┃ pos   ┃ type    ┃ count ┃ nulls ┃ unique ┃ mean        ┃ std        ┃ min     ┃ p25      ┃ p50     ┃ p75     ┃ max     ┃
┡━━━━━━━━━━━━━━━━━━━╇━━━━━━━╇━━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━┩
│ string            │ int16 │ string  │ int64 │ int64 │ int64  │ float64     │ float64    │ float64 │ float64  │ float64 │ float64 │ float64 │
├───────────────────┼───────┼─────────┼───────┼───────┼────────┼─────────────┼────────────┼─────────┼──────────┼─────────┼─────────┼─────────┤
│ flipper_length_mm │     2 │ int64   │   344 │     2 │     55 │  200.915205 │  14.061714 │   172.0 │  190.000 │  197.00 │   213.0 │   231.0 │
│ body_mass_g       │     3 │ int64   │   344 │     2 │     94 │ 4201.754386 │ 801.954536 │  2700.0 │ 3550.000 │ 4050.00 │  4750.0 │  6300.0 │
│ year              │     4 │ int64   │   344 │     0 │      3 │ 2008.029070 │   0.818356 │  2007.0 │ 2007.000 │ 2008.00 │  2009.0 │  2009.0 │
│ bill_length_mm    │     0 │ float64 │   344 │     2 │    164 │   43.921930 │   5.459584 │    32.1 │   39.225 │   44.45 │    48.5 │    59.6 │
│ bill_depth_mm     │     1 │ float64 │   344 │     2 │     80 │   17.151170 │   1.974793 │    13.1 │   15.600 │   17.30 │    18.7 │    21.5 │
└───────────────────┴───────┴─────────┴───────┴───────┴────────┴─────────────┴────────────┴─────────┴──────────┴─────────┴─────────┴─────────┘

>>> p.select(s.of_type("string")).describe()

┏━━━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━┓
┃ name    ┃ pos   ┃ type   ┃ count ┃ nulls ┃ unique ┃ mode   ┃
┡━━━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━┩
│ string  │ int16 │ string │ int64 │ int64 │ int64  │ string │
├─────────┼───────┼────────┼───────┼───────┼────────┼────────┤
│ sex     │     2 │ string │   344 │    11 │      2 │ male   │
│ species │     0 │ string │   344 │     0 │      3 │ Adelie │
│ island  │     1 │ string │   344 │     0 │      3 │ Biscoe │
└─────────┴───────┴────────┴───────┴───────┴────────┴────────┘

difference

difference(table, *rest, distinct=True)

Compute the set difference of multiple table expressions.

The input tables must have identical schemas.

Parameters

Name	Type	Description	Default
table	Table	A table expression	required
*rest	Table	Additional table expressions	`()`
distinct	bool	Only diff distinct rows not occurring in the calling table	`True`

Returns

Name	Type	Description
	Table	The rows present in `self` that are not present in `tables`.

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t1 = ibis.memtable({"a": [1, 2]})
>>> t1

┏━━━━━━━┓
┃ a     ┃
┡━━━━━━━┩
│ int64 │
├───────┤
│     1 │
│     2 │
└───────┘

>>> t2 = ibis.memtable({"a": [2, 3]})
>>> t2

┏━━━━━━━┓
┃ a     ┃
┡━━━━━━━┩
│ int64 │
├───────┤
│     2 │
│     3 │
└───────┘

>>> t1.difference(t2)

┏━━━━━━━┓
┃ a     ┃
┡━━━━━━━┩
│ int64 │
├───────┤
│     1 │
└───────┘

distinct

distinct(on=None, keep='first')

Return a Table with duplicate rows removed.

Similar to pandas.DataFrame.drop_duplicates().

Some backends do not support keep='last'

Parameters

Name	Type	Description	Default
on	str \| Iterable[str] \| `s`.`Selector` \| None	Only consider certain columns for identifying duplicates. By default deduplicate all of the columns.	`None`
keep	Literal['first', 'last'] \| None	Determines which duplicates to keep. - `"first"`: Drop duplicates except for the first occurrence. - `"last"`: Drop duplicates except for the last occurrence. - `None`: Drop all duplicates	`'first'`

Examples

>>> import ibis
>>> import ibis.examples as ex
>>> import ibis.selectors as s
>>> ibis.options.interactive = True
>>> t = ex.penguins.fetch()
>>> t

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
│ Adelie  │ Torgersen │           NULL │          NULL │              NULL │        NULL │ NULL   │  2007 │
│ Adelie  │ Torgersen │           36.7 │          19.3 │               193 │        3450 │ female │  2007 │
│ Adelie  │ Torgersen │           39.3 │          20.6 │               190 │        3650 │ male   │  2007 │
│ Adelie  │ Torgersen │           38.9 │          17.8 │               181 │        3625 │ female │  2007 │
│ Adelie  │ Torgersen │           39.2 │          19.6 │               195 │        4675 │ male   │  2007 │
│ Adelie  │ Torgersen │           34.1 │          18.1 │               193 │        3475 │ NULL   │  2007 │
│ Adelie  │ Torgersen │           42.0 │          20.2 │               190 │        4250 │ NULL   │  2007 │
│ …       │ …         │              … │             … │                 … │           … │ …      │     … │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

Compute the distinct rows of a subset of columns

>>> t[["species", "island"]].distinct().order_by(s.all())

┏━━━━━━━━━━━┳━━━━━━━━━━━┓
┃ species   ┃ island    ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━┩
│ string    │ string    │
├───────────┼───────────┤
│ Adelie    │ Biscoe    │
│ Adelie    │ Dream     │
│ Adelie    │ Torgersen │
│ Chinstrap │ Dream     │
│ Gentoo    │ Biscoe    │
└───────────┴───────────┘

Drop all duplicate rows except the first

>>> t.distinct(on=["species", "island"], keep="first").order_by(s.all())

┏━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species   ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string    │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├───────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie    │ Biscoe    │           37.8 │          18.3 │               174 │        3400 │ female │  2007 │
│ Adelie    │ Dream     │           39.5 │          16.7 │               178 │        3250 │ female │  2007 │
│ Adelie    │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Chinstrap │ Dream     │           46.5 │          17.9 │               192 │        3500 │ female │  2007 │
│ Gentoo    │ Biscoe    │           46.1 │          13.2 │               211 │        4500 │ female │  2007 │
└───────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

Drop all duplicate rows except the last

>>> t.distinct(on=["species", "island"], keep="last").order_by(s.all())

┏━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species   ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string    │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├───────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie    │ Biscoe    │           42.7 │          18.3 │               196 │        4075 │ male   │  2009 │
│ Adelie    │ Dream     │           41.5 │          18.5 │               201 │        4000 │ male   │  2009 │
│ Adelie    │ Torgersen │           43.1 │          19.2 │               197 │        3500 │ male   │  2009 │
│ Chinstrap │ Dream     │           50.2 │          18.7 │               198 │        3775 │ female │  2009 │
│ Gentoo    │ Biscoe    │           49.9 │          16.1 │               213 │        5400 │ male   │  2009 │
└───────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

Drop all duplicated rows

>>> expr = t.distinct(on=["species", "island", "year", "bill_length_mm"], keep=None)
>>> expr.count()

┌─────┐
│ 273 │
└─────┘

>>> t.count()

┌─────┐
│ 344 │
└─────┘

You can pass selectors to on

>>> t.distinct(on=~s.numeric())

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Biscoe    │           37.8 │          18.3 │               174 │        3400 │ female │  2007 │
│ Gentoo  │ Biscoe    │           46.1 │          13.2 │               211 │        4500 │ female │  2007 │
│ Adelie  │ Biscoe    │           37.7 │          18.7 │               180 │        3600 │ male   │  2007 │
│ Gentoo  │ Biscoe    │           50.0 │          16.3 │               230 │        5700 │ male   │  2007 │
│ Gentoo  │ Biscoe    │           44.5 │          14.3 │               216 │        4100 │ NULL   │  2007 │
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           34.1 │          18.1 │               193 │        3475 │ NULL   │  2007 │
│ Adelie  │ Dream     │           37.2 │          18.1 │               178 │        3900 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Dream     │           39.5 │          16.7 │               178 │        3250 │ female │  2007 │
│ …       │ …         │              … │             … │                 … │           … │ …      │     … │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

The only valid values of keep are "first", "last" and None.

>>> t.distinct(on="species", keep="second")

---------------------------------------------------------------------------
IbisError                                 Traceback (most recent call last)
Cell In[122], line 1
----> 1 t.distinct(on="species", keep="second")  

File ~/work/ibis/ibis/ibis/expr/types/relations.py:1199, in Table.distinct(self, on, keep)
   1197     method = keep
   1198 else:
-> 1199     raise com.IbisError(
   1200         f"Invalid value for `keep`: {keep!r}, must be 'first', 'last' or None"
   1201     )
   1203 aggs = {col.get_name(): getattr(col, method)() for col in (~on).expand(self)}
   1204 res = self.aggregate(aggs, by=on, having=having)

IbisError: Invalid value for `keep`: 'second', must be 'first', 'last' or None

drop

drop(*fields)

Remove fields from a table.

Parameters

Name	Type	Description	Default
fields	str \| `Selector`	Fields to drop. Strings and selectors are accepted.	`()`

Returns

Name	Type	Description
	Table	A table with all columns matching `fields` removed.

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> t

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
│ Adelie  │ Torgersen │           NULL │          NULL │              NULL │        NULL │ NULL   │  2007 │
│ Adelie  │ Torgersen │           36.7 │          19.3 │               193 │        3450 │ female │  2007 │
│ Adelie  │ Torgersen │           39.3 │          20.6 │               190 │        3650 │ male   │  2007 │
│ Adelie  │ Torgersen │           38.9 │          17.8 │               181 │        3625 │ female │  2007 │
│ Adelie  │ Torgersen │           39.2 │          19.6 │               195 │        4675 │ male   │  2007 │
│ Adelie  │ Torgersen │           34.1 │          18.1 │               193 │        3475 │ NULL   │  2007 │
│ Adelie  │ Torgersen │           42.0 │          20.2 │               190 │        4250 │ NULL   │  2007 │
│ …       │ …         │              … │             … │                 … │           … │ …      │     … │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

Drop one or more columns

>>> t.drop("species").head()

┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
│ Torgersen │           NULL │          NULL │              NULL │        NULL │ NULL   │  2007 │
│ Torgersen │           36.7 │          19.3 │               193 │        3450 │ female │  2007 │
└───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

>>> t.drop("species", "bill_length_mm").head()

┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ island    ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string    │ float64       │ int64             │ int64       │ string │ int64 │
├───────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Torgersen │          18.7 │               181 │        3750 │ male   │  2007 │
│ Torgersen │          17.4 │               186 │        3800 │ female │  2007 │
│ Torgersen │          18.0 │               195 │        3250 │ female │  2007 │
│ Torgersen │          NULL │              NULL │        NULL │ NULL   │  2007 │
│ Torgersen │          19.3 │               193 │        3450 │ female │  2007 │
└───────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

Drop with selectors, mix and match

>>> import ibis.selectors as s
>>> t.drop("species", s.startswith("bill_")).head()

┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ island    ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string    │ int64             │ int64       │ string │ int64 │
├───────────┼───────────────────┼─────────────┼────────┼───────┤
│ Torgersen │               181 │        3750 │ male   │  2007 │
│ Torgersen │               186 │        3800 │ female │  2007 │
│ Torgersen │               195 │        3250 │ female │  2007 │
│ Torgersen │              NULL │        NULL │ NULL   │  2007 │
│ Torgersen │               193 │        3450 │ female │  2007 │
└───────────┴───────────────────┴─────────────┴────────┴───────┘

drop_null

drop_null(subset=None, how='any')

Remove rows with null values from the table.

Parameters

Name	Type	Description	Default
subset	Sequence[str] \| str \| None	Columns names to consider when dropping nulls. By default all columns are considered.	`None`
how	Literal['any', 'all']	Determine whether a row is removed if there is at least one null value in the row (`'any'`), or if all row values are null (`'all'`).	`'any'`

Returns

Name	Type	Description
	Table	Table expression

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> t

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
│ Adelie  │ Torgersen │           NULL │          NULL │              NULL │        NULL │ NULL   │  2007 │
│ Adelie  │ Torgersen │           36.7 │          19.3 │               193 │        3450 │ female │  2007 │
│ Adelie  │ Torgersen │           39.3 │          20.6 │               190 │        3650 │ male   │  2007 │
│ Adelie  │ Torgersen │           38.9 │          17.8 │               181 │        3625 │ female │  2007 │
│ Adelie  │ Torgersen │           39.2 │          19.6 │               195 │        4675 │ male   │  2007 │
│ Adelie  │ Torgersen │           34.1 │          18.1 │               193 │        3475 │ NULL   │  2007 │
│ Adelie  │ Torgersen │           42.0 │          20.2 │               190 │        4250 │ NULL   │  2007 │
│ …       │ …         │              … │             … │                 … │           … │ …      │     … │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

>>> t.count()

┌─────┐
│ 344 │
└─────┘

>>> t.drop_null(["bill_length_mm", "body_mass_g"]).count()

┌─────┐
│ 342 │
└─────┘

>>> t.drop_null(how="all").count()  # no rows where all columns are null

┌─────┐
│ 344 │
└─────┘

dropna

dropna(subset=None, how='any')

Deprecated - use drop_null instead.

equals

equals(other)

Return whether this expression is structurally equivalent to other.

If you want to produce an equality expression, use == syntax.

Parameters

Name	Type	Description	Default
other		Another expression	required

Examples

>>> import ibis
>>> t1 = ibis.table(dict(a="int"), name="t")
>>> t2 = ibis.table(dict(a="int"), name="t")
>>> t1.equals(t2)

True

>>> v = ibis.table(dict(a="string"), name="v")
>>> t1.equals(v)

False

execute

execute(limit='default', params=None, **kwargs)

Execute an expression against its backend if one exists.

Parameters

Name	Type	Description	Default
limit	int \| str \| None	An integer to effect a specific row limit. A value of `None` means “no limit”. The default is in `ibis/config.py`.	`'default'`
params	Mapping[`ir`.`Value`, Any] \| None	Mapping of scalar parameter expressions to value	`None`
kwargs	Any	Keyword arguments	`{}`

Examples

>>> import ibis
>>> t = ibis.examples.penguins.fetch()
>>> t.execute()

	species	island	bill_length_mm	bill_depth_mm	flipper_length_mm	body_mass_g	sex	year
0	Adelie	Torgersen	39.1	18.7	181.0	3750.0	male	2007
1	Adelie	Torgersen	39.5	17.4	186.0	3800.0	female	2007
2	Adelie	Torgersen	40.3	18.0	195.0	3250.0	female	2007
3	Adelie	Torgersen	NaN	NaN	NaN	NaN	None	2007
4	Adelie	Torgersen	36.7	19.3	193.0	3450.0	female	2007
...	...	...	...	...	...	...	...	...
339	Chinstrap	Dream	55.8	19.8	207.0	4000.0	male	2009
340	Chinstrap	Dream	43.5	18.1	202.0	3400.0	female	2009
341	Chinstrap	Dream	49.6	18.2	193.0	3775.0	male	2009
342	Chinstrap	Dream	50.8	19.0	210.0	4100.0	male	2009
343	Chinstrap	Dream	50.2	18.7	198.0	3775.0	female	2009

344 rows × 8 columns

Scalar parameters can be supplied dynamically during execution.

>>> species = ibis.param("string")
>>> expr = t.filter(t.species == species).order_by(t.bill_length_mm)
>>> expr.execute(limit=3, params={species: "Gentoo"})

	species	island	bill_length_mm	bill_depth_mm	flipper_length_mm	body_mass_g	sex	year
0	Gentoo	Biscoe	40.9	13.7	214	4650	female	2007
1	Gentoo	Biscoe	41.7	14.7	210	4700	female	2009
2	Gentoo	Biscoe	42.0	13.5	210	4150	female	2007

fill_null

fill_null(replacements)

Fill null values in a table expression.

There is potential lack of type stability with the fill_null API

For example, different library versions may impact whether a given backend promotes integer replacement values to floats.

Parameters

Name	Type	Description	Default
replacements	`ir`.`Scalar` \| Mapping[str, `ir`.`Scalar`]	Value with which to fill nulls. If `replacements` is a mapping, the keys are column names that map to their replacement value. If passed as a scalar all columns are filled with that value.	required

Returns

Name	Type	Description
	Table	Table expression

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> t.sex

┏━━━━━━━━┓
┃ sex    ┃
┡━━━━━━━━┩
│ string │
├────────┤
│ male   │
│ female │
│ female │
│ NULL   │
│ female │
│ male   │
│ female │
│ male   │
│ NULL   │
│ NULL   │
│ …      │
└────────┘

>>> t.fill_null({"sex": "unrecorded"}).sex

┏━━━━━━━━━━━━┓
┃ sex        ┃
┡━━━━━━━━━━━━┩
│ string     │
├────────────┤
│ male       │
│ female     │
│ female     │
│ unrecorded │
│ female     │
│ male       │
│ female     │
│ male       │
│ unrecorded │
│ unrecorded │
│ …          │
└────────────┘

fillna

fillna(replacements)

Deprecated - use fill_null instead.

filter

filter(*predicates)

Select rows from table based on predicates.

Parameters

Name	Type	Description	Default
predicates	`ir`.`BooleanValue` \| Sequence[`ir`.`BooleanValue`] \| `IfAnyAll`	Boolean value expressions used to select rows in `table`.	`()`

Returns

Name	Type	Description
	Table	Filtered table expression

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> t

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
│ Adelie  │ Torgersen │           NULL │          NULL │              NULL │        NULL │ NULL   │  2007 │
│ Adelie  │ Torgersen │           36.7 │          19.3 │               193 │        3450 │ female │  2007 │
│ Adelie  │ Torgersen │           39.3 │          20.6 │               190 │        3650 │ male   │  2007 │
│ Adelie  │ Torgersen │           38.9 │          17.8 │               181 │        3625 │ female │  2007 │
│ Adelie  │ Torgersen │           39.2 │          19.6 │               195 │        4675 │ male   │  2007 │
│ Adelie  │ Torgersen │           34.1 │          18.1 │               193 │        3475 │ NULL   │  2007 │
│ Adelie  │ Torgersen │           42.0 │          20.2 │               190 │        4250 │ NULL   │  2007 │
│ …       │ …         │              … │             … │                 … │           … │ …      │     … │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

>>> t.filter([t.species == "Adelie", t.body_mass_g > 3500]).sex.value_counts().drop_null(
...     "sex"
... ).order_by("sex")

┏━━━━━━━━┳━━━━━━━━━━━┓
┃ sex    ┃ sex_count ┃
┡━━━━━━━━╇━━━━━━━━━━━┩
│ string │ int64     │
├────────┼───────────┤
│ female │        22 │
│ male   │        68 │
└────────┴───────────┘

get_backend

get_backend()

Get the current Ibis backend of the expression.

Returns

Name	Type	Description
	`BaseBackend`	The Ibis backend.

Examples

>>> import ibis
>>> con = ibis.duckdb.connect()
>>> t = con.create_table("t", {"id": [1, 2, 3]})
>>> t.get_backend()

<ibis.backends.duckdb.Backend at 0x7fff86d6c690>

get_name

get_name()

Return the fully qualified name of the table.

Examples

>>> import ibis
>>> con = ibis.duckdb.connect()
>>> t = con.create_table("t", {"id": [1, 2, 3]})
>>> t.get_name()

'memory.main.t'

group_by

group_by(*by, **key_exprs)

Create a grouped table expression.

Similar to SQL’s GROUP BY statement, or pandas .groupby() method.

Parameters

Name	Type	Description	Default
by	str \| `ir`.`Value` \| Iterable[str] \| Iterable[`ir`.`Value`] \| None	Grouping expressions	`()`
key_exprs	str \| `ir`.`Value` \| Iterable[str] \| Iterable[`ir`.`Value`]	Named grouping expressions	`{}`

Returns

Name	Type	Description
	GroupedTable	A grouped table expression

Examples

>>> import ibis
>>> from ibis import _
>>> ibis.options.interactive = True
>>> t = ibis.memtable(
...     {
...         "fruit": ["apple", "apple", "banana", "orange"],
...         "price": [0.5, 0.5, 0.25, 0.33],
...     }
... )
>>> t

┏━━━━━━━━┳━━━━━━━━━┓
┃ fruit  ┃ price   ┃
┡━━━━━━━━╇━━━━━━━━━┩
│ string │ float64 │
├────────┼─────────┤
│ apple  │    0.50 │
│ apple  │    0.50 │
│ banana │    0.25 │
│ orange │    0.33 │
└────────┴─────────┘

>>> t.group_by("fruit").agg(total_cost=_.price.sum(), avg_cost=_.price.mean()).order_by(
...     "fruit"
... )

┏━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━┓
┃ fruit  ┃ total_cost ┃ avg_cost ┃
┡━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━┩
│ string │ float64    │ float64  │
├────────┼────────────┼──────────┤
│ apple  │       1.00 │     0.50 │
│ banana │       0.25 │     0.25 │
│ orange │       0.33 │     0.33 │
└────────┴────────────┴──────────┘

head

head(n=5)

Select the first n rows of a table.

The result set is not deterministic without a call to order_by.

Parameters

Name	Type	Description	Default
n	int	Number of rows to include	`5`

Returns

Name	Type	Description
	Table	`self` limited to `n` rows

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.memtable({"a": [1, 1, 2], "b": ["c", "a", "a"]})
>>> t

┏━━━━━━━┳━━━━━━━━┓
┃ a     ┃ b      ┃
┡━━━━━━━╇━━━━━━━━┩
│ int64 │ string │
├───────┼────────┤
│     1 │ c      │
│     1 │ a      │
│     2 │ a      │
└───────┴────────┘

>>> t.head(2)

┏━━━━━━━┳━━━━━━━━┓
┃ a     ┃ b      ┃
┡━━━━━━━╇━━━━━━━━┩
│ int64 │ string │
├───────┼────────┤
│     1 │ c      │
│     1 │ a      │
└───────┴────────┘

info

info()

Return summary information about a table.

Returns

Name	Type	Description
	Table	Summary of `self`

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> t.info()

┏━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━┓
┃ name              ┃ type    ┃ nullable ┃ nulls ┃ non_nulls ┃ null_frac ┃ pos   ┃
┡━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━┩
│ string            │ string  │ boolean  │ int64 │ int64     │ float64   │ int16 │
├───────────────────┼─────────┼──────────┼───────┼───────────┼───────────┼───────┤
│ species           │ string  │ True     │     0 │       344 │  0.000000 │     0 │
│ island            │ string  │ True     │     0 │       344 │  0.000000 │     1 │
│ bill_length_mm    │ float64 │ True     │     2 │       342 │  0.005814 │     2 │
│ bill_depth_mm     │ float64 │ True     │     2 │       342 │  0.005814 │     3 │
│ flipper_length_mm │ int64   │ True     │     2 │       342 │  0.005814 │     4 │
│ body_mass_g       │ int64   │ True     │     2 │       342 │  0.005814 │     5 │
│ sex               │ string  │ True     │    11 │       333 │  0.031977 │     6 │
│ year              │ int64   │ True     │     0 │       344 │  0.000000 │     7 │
└───────────────────┴─────────┴──────────┴───────┴───────────┴───────────┴───────┘

intersect

intersect(table, *rest, distinct=True)

Compute the set intersection of multiple table expressions.

The input tables must have identical schemas.

Parameters

Name	Type	Description	Default
table	Table	A table expression	required
*rest	Table	Additional table expressions	`()`
distinct	bool	Only return distinct rows	`True`

Returns

Name	Type	Description
	Table	A new table containing the intersection of all input tables.

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t1 = ibis.memtable({"a": [1, 2, 2]})
>>> t1

┏━━━━━━━┓
┃ a     ┃
┡━━━━━━━┩
│ int64 │
├───────┤
│     1 │
│     2 │
│     2 │
└───────┘

>>> t2 = ibis.memtable({"a": [2, 2, 3]})
>>> t2

┏━━━━━━━┓
┃ a     ┃
┡━━━━━━━┩
│ int64 │
├───────┤
│     2 │
│     2 │
│     3 │
└───────┘

>>> t1.intersect(t2)

┏━━━━━━━┓
┃ a     ┃
┡━━━━━━━┩
│ int64 │
├───────┤
│     2 │
└───────┘

>>> t1.intersect(t2, distinct=False)

┏━━━━━━━┓
┃ a     ┃
┡━━━━━━━┩
│ int64 │
├───────┤
│     2 │
│     2 │
└───────┘

More than two table expressions can be intersected at once.

>>> t3 = ibis.memtable({"a": [2, 3, 3]})
>>> t1.intersect(t2, t3)

┏━━━━━━━┓
┃ a     ┃
┡━━━━━━━┩
│ int64 │
├───────┤
│     2 │
└───────┘

join

join(left, right, predicates=(), how='inner', *, lname='', rname='{name}_right')

Perform a join between two tables.

Parameters

Name	Type	Description	Default
left	Table	Left table to join	required
right	Table	Right table to join	required
predicates	str \| Sequence[str \| `ir`.`BooleanColumn` \| Literal[True] \| Literal[False] \| tuple[str \| `ir`.`Column` \| `ir`.`Deferred`, str \| `ir`.`Column` \| `ir`.`Deferred`]]	Condition(s) to join on. See examples for details.	`()`
how	`JoinKind`	Join method, e.g. `"inner"` or `"left"`.	`'inner'`
lname	str	A format string to use to rename overlapping columns in the left table (e.g. `"left_{name}"`).	`''`
rname	str	A format string to use to rename overlapping columns in the right table (e.g. `"right_{name}"`).	`'{name}_right'`

Examples

>>> import ibis
>>> from ibis import _
>>> ibis.options.interactive = True
>>> movies = ibis.examples.ml_latest_small_movies.fetch()
>>> movies.head()

┏━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ movieId ┃ title                              ┃ genres                                      ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ int64   │ string                             │ string                                      │
├─────────┼────────────────────────────────────┼─────────────────────────────────────────────┤
│       1 │ Toy Story (1995)                   │ Adventure|Animation|Children|Comedy|Fantasy │
│       2 │ Jumanji (1995)                     │ Adventure|Children|Fantasy                  │
│       3 │ Grumpier Old Men (1995)            │ Comedy|Romance                              │
│       4 │ Waiting to Exhale (1995)           │ Comedy|Drama|Romance                        │
│       5 │ Father of the Bride Part II (1995) │ Comedy                                      │
└─────────┴────────────────────────────────────┴─────────────────────────────────────────────┘

>>> ratings = ibis.examples.ml_latest_small_ratings.fetch().drop("timestamp")
>>> ratings.head()

┏━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┓
┃ userId ┃ movieId ┃ rating  ┃
┡━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━┩
│ int64  │ int64   │ float64 │
├────────┼─────────┼─────────┤
│      1 │       1 │     4.0 │
│      1 │       3 │     4.0 │
│      1 │       6 │     4.0 │
│      1 │      47 │     5.0 │
│      1 │      50 │     5.0 │
└────────┴─────────┴─────────┘

Equality left join on the shared movieId column. Note the _right suffix added to all overlapping columns from the right table (in this case only the “movieId” column).

>>> ratings.join(movies, "movieId", how="left").head(5)

┏━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ userId ┃ movieId ┃ rating  ┃ movieId_right ┃ title                       ┃ genres                                      ┃
┡━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ int64  │ int64   │ float64 │ int64         │ string                      │ string                                      │
├────────┼─────────┼─────────┼───────────────┼─────────────────────────────┼─────────────────────────────────────────────┤
│      1 │       1 │     4.0 │             1 │ Toy Story (1995)            │ Adventure|Animation|Children|Comedy|Fantasy │
│      1 │       3 │     4.0 │             3 │ Grumpier Old Men (1995)     │ Comedy|Romance                              │
│      1 │       6 │     4.0 │             6 │ Heat (1995)                 │ Action|Crime|Thriller                       │
│      1 │      47 │     5.0 │            47 │ Seven (a.k.a. Se7en) (1995) │ Mystery|Thriller                            │
│      1 │      50 │     5.0 │            50 │ Usual Suspects, The (1995)  │ Crime|Mystery|Thriller                      │
└────────┴─────────┴─────────┴───────────────┴─────────────────────────────┴─────────────────────────────────────────────┘

Explicit equality join using the default how value of "inner". Note how there is no _right suffix added to the movieId column since this is an inner join and the movieId column is part of the join condition.

>>> ratings.join(movies, ratings.movieId == movies.movieId).head(5)

┏━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ userId ┃ movieId ┃ rating  ┃ title                       ┃ genres                                      ┃
┡━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ int64  │ int64   │ float64 │ string                      │ string                                      │
├────────┼─────────┼─────────┼─────────────────────────────┼─────────────────────────────────────────────┤
│      1 │       1 │     4.0 │ Toy Story (1995)            │ Adventure|Animation|Children|Comedy|Fantasy │
│      1 │       3 │     4.0 │ Grumpier Old Men (1995)     │ Comedy|Romance                              │
│      1 │       6 │     4.0 │ Heat (1995)                 │ Action|Crime|Thriller                       │
│      1 │      47 │     5.0 │ Seven (a.k.a. Se7en) (1995) │ Mystery|Thriller                            │
│      1 │      50 │     5.0 │ Usual Suspects, The (1995)  │ Crime|Mystery|Thriller                      │
└────────┴─────────┴─────────┴─────────────────────────────┴─────────────────────────────────────────────┘

>>> tags = ibis.examples.ml_latest_small_tags.fetch()
>>> tags.head()

┏━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━┓
┃ userId ┃ movieId ┃ tag             ┃ timestamp  ┃
┡━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━┩
│ int64  │ int64   │ string          │ int64      │
├────────┼─────────┼─────────────────┼────────────┤
│      2 │   60756 │ funny           │ 1445714994 │
│      2 │   60756 │ Highly quotable │ 1445714996 │
│      2 │   60756 │ will ferrell    │ 1445714992 │
│      2 │   89774 │ Boxing story    │ 1445715207 │
│      2 │   89774 │ MMA             │ 1445715200 │
└────────┴─────────┴─────────────────┴────────────┘

You can join on multiple columns/conditions by passing in a sequence. Find all instances where a user both tagged and rated a movie:

>>> tags.join(ratings, ["userId", "movieId"]).head(5).order_by("userId")

┏━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━┓
┃ userId ┃ movieId ┃ tag            ┃ timestamp  ┃ rating  ┃
┡━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━┩
│ int64  │ int64   │ string         │ int64      │ float64 │
├────────┼─────────┼────────────────┼────────────┼─────────┤
│     62 │       2 │ Robin Williams │ 1528843907 │     4.0 │
│     62 │     110 │ sword fight    │ 1528152535 │     4.5 │
│     62 │     410 │ gothic         │ 1525636609 │     4.5 │
│     62 │    2023 │ mafia          │ 1525636733 │     5.0 │
│     62 │    2124 │ quirky         │ 1525636846 │     5.0 │
└────────┴─────────┴────────────────┴────────────┴─────────┘

To self-join a table with itself, you need to call .view() on one of the arguments so the two tables are distinct from each other.

For crafting more complex join conditions, a valid form of a join condition is a 2-tuple like ({left_key}, {right_key}), where each key can be

a Column
Deferred expression
lambda of the form (Table) -> Column

For example, to find all movies pairings that received the same (ignoring case) tags:

>>> movie_tags = tags["movieId", "tag"]
>>> view = movie_tags.view()
>>> movie_tags.join(
...     view,
...     [
...         movie_tags.movieId != view.movieId,
...         (_.tag.lower(), lambda t: t.tag.lower()),
...     ],
... ).head().order_by(("movieId", "movieId_right"))

┏━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓
┃ movieId ┃ tag               ┃ movieId_right ┃ tag_right         ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━┩
│ int64   │ string            │ int64         │ string            │
├─────────┼───────────────────┼───────────────┼───────────────────┤
│   60756 │ funny             │          1732 │ funny             │
│   60756 │ Highly quotable   │          1732 │ Highly quotable   │
│   89774 │ Tom Hardy         │        139385 │ tom hardy         │
│  106782 │ drugs             │          1732 │ drugs             │
│  106782 │ Leonardo DiCaprio │          5989 │ Leonardo DiCaprio │
└─────────┴───────────────────┴───────────────┴───────────────────┘

limit

limit(n, offset=0)

Select n rows from self starting at offset.

The result set is not deterministic without a call to order_by.

Parameters

Name	Type	Description	Default
n	int \| None	Number of rows to include. If `None`, the entire table is selected starting from `offset`.	required
offset	int	Number of rows to skip first	`0`

Returns

Name	Type	Description
	Table	The first `n` rows of `self` starting at `offset`

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.memtable({"a": [1, 1, 2], "b": ["c", "a", "a"]})
>>> t

┏━━━━━━━┳━━━━━━━━┓
┃ a     ┃ b      ┃
┡━━━━━━━╇━━━━━━━━┩
│ int64 │ string │
├───────┼────────┤
│     1 │ c      │
│     1 │ a      │
│     2 │ a      │
└───────┴────────┘

>>> t.limit(2)

┏━━━━━━━┳━━━━━━━━┓
┃ a     ┃ b      ┃
┡━━━━━━━╇━━━━━━━━┩
│ int64 │ string │
├───────┼────────┤
│     1 │ c      │
│     1 │ a      │
└───────┴────────┘

You can use None with offset to slice starting from a particular row

>>> t.limit(None, offset=1)

┏━━━━━━━┳━━━━━━━━┓
┃ a     ┃ b      ┃
┡━━━━━━━╇━━━━━━━━┩
│ int64 │ string │
├───────┼────────┤
│     1 │ a      │
│     2 │ a      │
└───────┴────────┘

mutate

mutate(*exprs, **mutations)

Add columns to a table expression.

Parameters

Name	Type	Description	Default
exprs	Sequence[`ir`.`Expr`] \| None	List of named expressions to add as columns	`()`
mutations	`ir`.`Value`	Named expressions using keyword arguments	`{}`

Returns

Name	Type	Description
	Table	Table expression with additional columns

Examples

>>> import ibis
>>> import ibis.selectors as s
>>> from ibis import _
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch().select("species", "year", "bill_length_mm")
>>> t

┏━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━━━━━┓
┃ species ┃ year  ┃ bill_length_mm ┃
┡━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━━━━━┩
│ string  │ int64 │ float64        │
├─────────┼───────┼────────────────┤
│ Adelie  │  2007 │           39.1 │
│ Adelie  │  2007 │           39.5 │
│ Adelie  │  2007 │           40.3 │
│ Adelie  │  2007 │           NULL │
│ Adelie  │  2007 │           36.7 │
│ Adelie  │  2007 │           39.3 │
│ Adelie  │  2007 │           38.9 │
│ Adelie  │  2007 │           39.2 │
│ Adelie  │  2007 │           34.1 │
│ Adelie  │  2007 │           42.0 │
│ …       │     … │              … │
└─────────┴───────┴────────────────┘

Add a new column from a per-element expression

>>> t.mutate(next_year=_.year + 1).head()

┏━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━┓
┃ species ┃ year  ┃ bill_length_mm ┃ next_year ┃
┡━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━┩
│ string  │ int64 │ float64        │ int64     │
├─────────┼───────┼────────────────┼───────────┤
│ Adelie  │  2007 │           39.1 │      2008 │
│ Adelie  │  2007 │           39.5 │      2008 │
│ Adelie  │  2007 │           40.3 │      2008 │
│ Adelie  │  2007 │           NULL │      2008 │
│ Adelie  │  2007 │           36.7 │      2008 │
└─────────┴───────┴────────────────┴───────────┘

Add a new column based on an aggregation. Note the automatic broadcasting.

>>> t.select("species", bill_demean=_.bill_length_mm - _.bill_length_mm.mean()).head()

┏━━━━━━━━━┳━━━━━━━━━━━━━┓
┃ species ┃ bill_demean ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━┩
│ string  │ float64     │
├─────────┼─────────────┤
│ Adelie  │    -4.82193 │
│ Adelie  │    -4.42193 │
│ Adelie  │    -3.62193 │
│ Adelie  │        NULL │
│ Adelie  │    -7.22193 │
└─────────┴─────────────┘

Mutate across multiple columns

>>> t.mutate(s.across(s.numeric() & ~s.cols("year"), _ - _.mean())).head()

┏━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━━━━━┓
┃ species ┃ year  ┃ bill_length_mm ┃
┡━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━━━━━┩
│ string  │ int64 │ float64        │
├─────────┼───────┼────────────────┤
│ Adelie  │  2007 │       -4.82193 │
│ Adelie  │  2007 │       -4.42193 │
│ Adelie  │  2007 │       -3.62193 │
│ Adelie  │  2007 │           NULL │
│ Adelie  │  2007 │       -7.22193 │
└─────────┴───────┴────────────────┘

nunique

nunique(where=None)

Compute the number of unique rows in the table.

Parameters

Name	Type	Description	Default
where	`ir`.`BooleanValue` \| None	Optional boolean expression to filter rows when counting.	`None`

Returns

Name	Type	Description
	`IntegerScalar`	Number of unique rows in the table

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.memtable({"a": ["foo", "bar", "bar"]})
>>> t

┏━━━━━━━━┓
┃ a      ┃
┡━━━━━━━━┩
│ string │
├────────┤
│ foo    │
│ bar    │
│ bar    │
└────────┘

>>> t.nunique()

┌───┐
│ 2 │
└───┘

>>> t.nunique(t.a != "foo")

┌───┐
│ 1 │
└───┘

order_by

order_by(*by)

Sort a table by one or more expressions.

Similar to pandas.DataFrame.sort_values().

Parameters

Name	Type	Description	Default
by	str \| `ir`.`Column` \| `s`.`Selector` \| Sequence[str] \| Sequence[`ir`.`Column`] \| Sequence[`s`.`Selector`] \| None	Expressions to sort the table by.	`()`

Returns

Name	Type	Description
	Table	Sorted table

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.memtable(
...     {
...         "a": [3, 2, 1, 3],
...         "b": ["a", "B", "c", "D"],
...         "c": [4, 6, 5, 7],
...     }
... )
>>> t

┏━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ a     ┃ b      ┃ c     ┃
┡━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ int64 │ string │ int64 │
├───────┼────────┼───────┤
│     3 │ a      │     4 │
│     2 │ B      │     6 │
│     1 │ c      │     5 │
│     3 │ D      │     7 │
└───────┴────────┴───────┘

Sort by b. Default is ascending. Note how capital letters come before lowercase

>>> t.order_by("b")

┏━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ a     ┃ b      ┃ c     ┃
┡━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ int64 │ string │ int64 │
├───────┼────────┼───────┤
│     2 │ B      │     6 │
│     3 │ D      │     7 │
│     3 │ a      │     4 │
│     1 │ c      │     5 │
└───────┴────────┴───────┘

Sort in descending order

>>> t.order_by(ibis.desc("b"))

┏━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ a     ┃ b      ┃ c     ┃
┡━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ int64 │ string │ int64 │
├───────┼────────┼───────┤
│     1 │ c      │     5 │
│     3 │ a      │     4 │
│     3 │ D      │     7 │
│     2 │ B      │     6 │
└───────┴────────┴───────┘

You can also use the deferred API to get the same result

>>> from ibis import _
>>> t.order_by(_.b.desc())

┏━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ a     ┃ b      ┃ c     ┃
┡━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ int64 │ string │ int64 │
├───────┼────────┼───────┤
│     1 │ c      │     5 │
│     3 │ a      │     4 │
│     3 │ D      │     7 │
│     2 │ B      │     6 │
└───────┴────────┴───────┘

Sort by multiple columns/expressions

>>> t.order_by(["a", _.c.desc()])

┏━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ a     ┃ b      ┃ c     ┃
┡━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ int64 │ string │ int64 │
├───────┼────────┼───────┤
│     1 │ c      │     5 │
│     2 │ B      │     6 │
│     3 │ D      │     7 │
│     3 │ a      │     4 │
└───────┴────────┴───────┘

You can actually pass arbitrary expressions to use as sort keys. For example, to ignore the case of the strings in column b

>>> t.order_by(_.b.lower())

┏━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ a     ┃ b      ┃ c     ┃
┡━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ int64 │ string │ int64 │
├───────┼────────┼───────┤
│     3 │ a      │     4 │
│     2 │ B      │     6 │
│     1 │ c      │     5 │
│     3 │ D      │     7 │
└───────┴────────┴───────┘

This means that shuffling a Table is super simple

>>> t.order_by(ibis.random())

┏━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ a     ┃ b      ┃ c     ┃
┡━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ int64 │ string │ int64 │
├───────┼────────┼───────┤
│     3 │ a      │     4 │
│     1 │ c      │     5 │
│     3 │ D      │     7 │
│     2 │ B      │     6 │
└───────┴────────┴───────┘

Selectors are allowed as sort keys and are a concise way to sort by multiple columns matching some criteria

>>> import ibis.selectors as s
>>> penguins = ibis.examples.penguins.fetch()
>>> penguins[["year", "island"]].value_counts().order_by(s.startswith("year"))

┏━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓
┃ year  ┃ island    ┃ year_island_count ┃
┡━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━┩
│ int64 │ string    │ int64             │
├───────┼───────────┼───────────────────┤
│  2007 │ Torgersen │                20 │
│  2007 │ Biscoe    │                44 │
│  2007 │ Dream     │                46 │
│  2008 │ Torgersen │                16 │
│  2008 │ Dream     │                34 │
│  2008 │ Biscoe    │                64 │
│  2009 │ Torgersen │                16 │
│  2009 │ Dream     │                44 │
│  2009 │ Biscoe    │                60 │
└───────┴───────────┴───────────────────┘

Use the across selector to apply a specific order to multiple columns

>>> penguins[["year", "island"]].value_counts().order_by(
...     s.across(s.startswith("year"), _.desc())
... )

┏━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓
┃ year  ┃ island    ┃ year_island_count ┃
┡━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━┩
│ int64 │ string    │ int64             │
├───────┼───────────┼───────────────────┤
│  2009 │ Biscoe    │                60 │
│  2009 │ Dream     │                44 │
│  2009 │ Torgersen │                16 │
│  2008 │ Biscoe    │                64 │
│  2008 │ Dream     │                34 │
│  2008 │ Torgersen │                16 │
│  2007 │ Dream     │                46 │
│  2007 │ Biscoe    │                44 │
│  2007 │ Torgersen │                20 │
└───────┴───────────┴───────────────────┘

pipe

pipe(f, *args, **kwargs)

Compose f with self.

Parameters

Name	Type	Description	Default
f		If the expression needs to be passed as anything other than the first argument to the function, pass a tuple with the argument name. For example, (f, ‘data’) if the function f expects a ‘data’ keyword	required
args	Any	Positional arguments to `f`	`()`
kwargs	Any	Keyword arguments to `f`	`{}`

Examples

>>> import ibis
>>> t = ibis.memtable(
...     {
...         "a": [5, 10, 15],
...         "b": ["a", "b", "c"],
...     }
... )
>>> f = lambda a: (a + 1).name("a")
>>> g = lambda a: (a * 2).name("a")
>>> result1 = t.a.pipe(f).pipe(g)
>>> result1

┏━━━━━━━┓
┃ a     ┃
┡━━━━━━━┩
│ int64 │
├───────┤
│    12 │
│    22 │
│    32 │
└───────┘

>>> result2 = g(f(t.a))  # equivalent to the above
>>> result1.equals(result2)

True

Returns

Name	Type	Description
	`Expr`	Result type of passed function

pivot_longer

pivot_longer(
    col,
    *,
    names_to='name',
    names_pattern='(.+)',
    names_transform=None,
    values_to='value',
    values_transform=None,
)

Transform a table from wider to longer.

Parameters

Name	Type	Description	Default
col	str \| `s`.`Selector`	String column name or selector.	required
names_to	str \| Iterable[str]	A string or iterable of strings indicating how to name the new pivoted columns.	`'name'`
names_pattern	str \| re.Pattern	Pattern to use to extract column names from the input. By default the entire column name is extracted.	`'(.+)'`
names_transform	Callable[[str], `ir`.`Value`] \| Mapping[str, Callable[[str], `ir`.`Value`]] \| None	Function or mapping of a name in `names_to` to a function to transform a column name to a value.	`None`
values_to	str	Name of the pivoted value column.	`'value'`
values_transform	Callable[[`ir`.`Value`], `ir`.`Value`] \| Deferred \| None	Apply a function to the value column. This can be a lambda or deferred expression.	`None`

Returns

Name	Type	Description
	Table	Pivoted table

Examples

Basic usage

>>> import ibis
>>> import ibis.selectors as s
>>> from ibis import _
>>> ibis.options.interactive = True
>>> relig_income = ibis.examples.relig_income_raw.fetch()
>>> relig_income

┏━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━━━━━━━━━┓
┃ religion                ┃ <$10k ┃ $10-20k ┃ $20-30k ┃ $30-40k ┃ $40-50k ┃ $50-75k ┃ $75-100k ┃ $100-150k ┃ >150k ┃ Don't know/refused ┃
┡━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━╇━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━━━━━━━━━┩
│ string                  │ int64 │ int64   │ int64   │ int64   │ int64   │ int64   │ int64    │ int64     │ int64 │ int64              │
├─────────────────────────┼───────┼─────────┼─────────┼─────────┼─────────┼─────────┼──────────┼───────────┼───────┼────────────────────┤
│ Agnostic                │    27 │      34 │      60 │      81 │      76 │     137 │      122 │       109 │    84 │                 96 │
│ Atheist                 │    12 │      27 │      37 │      52 │      35 │      70 │       73 │        59 │    74 │                 76 │
│ Buddhist                │    27 │      21 │      30 │      34 │      33 │      58 │       62 │        39 │    53 │                 54 │
│ Catholic                │   418 │     617 │     732 │     670 │     638 │    1116 │      949 │       792 │   633 │               1489 │
│ Don’t know/refused      │    15 │      14 │      15 │      11 │      10 │      35 │       21 │        17 │    18 │                116 │
│ Evangelical Prot        │   575 │     869 │    1064 │     982 │     881 │    1486 │      949 │       723 │   414 │               1529 │
│ Hindu                   │     1 │       9 │       7 │       9 │      11 │      34 │       47 │        48 │    54 │                 37 │
│ Historically Black Prot │   228 │     244 │     236 │     238 │     197 │     223 │      131 │        81 │    78 │                339 │
│ Jehovah's Witness       │    20 │      27 │      24 │      24 │      21 │      30 │       15 │        11 │     6 │                 37 │
│ Jewish                  │    19 │      19 │      25 │      25 │      30 │      95 │       69 │        87 │   151 │                162 │
│ …                       │     … │       … │       … │       … │       … │       … │        … │         … │     … │                  … │
└─────────────────────────┴───────┴─────────┴─────────┴─────────┴─────────┴─────────┴──────────┴───────────┴───────┴────────────────────┘

Here we convert column names not matching the selector for the religion column and convert those names into values

>>> relig_income.pivot_longer(~s.cols("religion"), names_to="income", values_to="count")

┏━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━┳━━━━━━━┓
┃ religion ┃ income             ┃ count ┃
┡━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━╇━━━━━━━┩
│ string   │ string             │ int64 │
├──────────┼────────────────────┼───────┤
│ Agnostic │ <$10k              │    27 │
│ Agnostic │ $10-20k            │    34 │
│ Agnostic │ $20-30k            │    60 │
│ Agnostic │ $30-40k            │    81 │
│ Agnostic │ $40-50k            │    76 │
│ Agnostic │ $50-75k            │   137 │
│ Agnostic │ $75-100k           │   122 │
│ Agnostic │ $100-150k          │   109 │
│ Agnostic │ >150k              │    84 │
│ Agnostic │ Don't know/refused │    96 │
│ …        │ …                  │     … │
└──────────┴────────────────────┴───────┘

Similarly for a different example dataset, we convert names to values but using a different selector and the default values_to value.

>>> world_bank_pop = ibis.examples.world_bank_pop_raw.fetch()
>>> world_bank_pop.head()

┏━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┓
┃ country ┃ indicator   ┃ 2000         ┃ 2001         ┃ 2002         ┃ 2003         ┃ 2004         ┃ 2005         ┃ 2006         ┃ 2007         ┃ 2008         ┃ 2009         ┃ 2010         ┃ 2011         ┃ 2012         ┃ 2013         ┃ 2014         ┃ 2015         ┃ 2016         ┃ 2017         ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━┩
│ string  │ string      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │ float64      │
├─────────┼─────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┤
│ ABW     │ SP.URB.TOTL │ 4.162500e+04 │ 4.202500e+04 │ 4.219400e+04 │ 4.227700e+04 │ 4.231700e+04 │ 4.239900e+04 │ 4.255500e+04 │ 4.272900e+04 │ 4.290600e+04 │ 4.307900e+04 │ 4.320600e+04 │ 4.349300e+04 │ 4.386400e+04 │ 4.422800e+04 │ 4.458800e+04 │ 4.494300e+04 │ 4.529700e+04 │ 4.564800e+04 │
│ ABW     │ SP.URB.GROW │ 1.664222e+00 │ 9.563731e-01 │ 4.013352e-01 │ 1.965172e-01 │ 9.456936e-02 │ 1.935880e-01 │ 3.672580e-01 │ 4.080490e-01 │ 4.133830e-01 │ 4.023963e-01 │ 2.943735e-01 │ 6.620631e-01 │ 8.493932e-01 │ 8.264135e-01 │ 8.106692e-01 │ 7.930256e-01 │ 7.845785e-01 │ 7.718989e-01 │
│ ABW     │ SP.POP.TOTL │ 8.910100e+04 │ 9.069100e+04 │ 9.178100e+04 │ 9.270100e+04 │ 9.354000e+04 │ 9.448300e+04 │ 9.560600e+04 │ 9.678700e+04 │ 9.799600e+04 │ 9.921200e+04 │ 1.003410e+05 │ 1.012880e+05 │ 1.021120e+05 │ 1.028800e+05 │ 1.035940e+05 │ 1.042570e+05 │ 1.048740e+05 │ 1.054390e+05 │
│ ABW     │ SP.POP.GROW │ 2.539234e+00 │ 1.768757e+00 │ 1.194718e+00 │ 9.973955e-01 │ 9.009892e-01 │ 1.003077e+00 │ 1.181566e+00 │ 1.227711e+00 │ 1.241397e+00 │ 1.233231e+00 │ 1.131541e+00 │ 9.393559e-01 │ 8.102306e-01 │ 7.493010e-01 │ 6.916153e-01 │ 6.379592e-01 │ 5.900625e-01 │ 5.372957e-01 │
│ AFE     │ SP.URB.TOTL │ 1.155517e+08 │ 1.197755e+08 │ 1.242275e+08 │ 1.288340e+08 │ 1.336475e+08 │ 1.387456e+08 │ 1.440267e+08 │ 1.492313e+08 │ 1.553838e+08 │ 1.617762e+08 │ 1.684561e+08 │ 1.754157e+08 │ 1.825587e+08 │ 1.901087e+08 │ 1.980733e+08 │ 2.065563e+08 │ 2.150833e+08 │ 2.237321e+08 │
└─────────┴─────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┘

>>> world_bank_pop.pivot_longer(s.matches(r"\d{4}"), names_to="year").head()

┏━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━━━┓
┃ country ┃ indicator   ┃ year   ┃ value   ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━━━┩
│ string  │ string      │ string │ float64 │
├─────────┼─────────────┼────────┼─────────┤
│ ABW     │ SP.URB.TOTL │ 2000   │ 41625.0 │
│ ABW     │ SP.URB.TOTL │ 2001   │ 42025.0 │
│ ABW     │ SP.URB.TOTL │ 2002   │ 42194.0 │
│ ABW     │ SP.URB.TOTL │ 2003   │ 42277.0 │
│ ABW     │ SP.URB.TOTL │ 2004   │ 42317.0 │
└─────────┴─────────────┴────────┴─────────┘

pivot_longer has some preprocessing capabilities like stripping a prefix and applying a function to column names

>>> billboard = ibis.examples.billboard.fetch()
>>> billboard

┏━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┓
┃ artist         ┃ track                   ┃ date_entered ┃ wk1   ┃ wk2   ┃ wk3   ┃ wk4   ┃ wk5   ┃ wk6   ┃ wk7   ┃ wk8   ┃ wk9   ┃ wk10  ┃ wk11  ┃ wk12  ┃ wk13  ┃ wk14  ┃ wk15  ┃ wk16  ┃ wk17  ┃ wk18  ┃ wk19  ┃ wk20  ┃ wk21  ┃ wk22  ┃ wk23  ┃ wk24  ┃ wk25  ┃ wk26  ┃ wk27  ┃ wk28  ┃ wk29  ┃ wk30  ┃ wk31  ┃ wk32  ┃ wk33  ┃ wk34  ┃ wk35  ┃ wk36  ┃ wk37  ┃ wk38  ┃ wk39  ┃ wk40  ┃ wk41  ┃ wk42  ┃ wk43  ┃ wk44  ┃ wk45  ┃ wk46  ┃ wk47  ┃ wk48  ┃ wk49  ┃ wk50  ┃ wk51  ┃ wk52  ┃ wk53  ┃ wk54  ┃ wk55  ┃ wk56  ┃ wk57  ┃ wk58  ┃ wk59  ┃ wk60  ┃ wk61  ┃ wk62  ┃ wk63  ┃ wk64  ┃ wk65  ┃ wk66   ┃ wk67   ┃ wk68   ┃ wk69   ┃ wk70   ┃ wk71   ┃ wk72   ┃ wk73   ┃ wk74   ┃ wk75   ┃ wk76   ┃
┡━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━┩
│ string         │ string                  │ date         │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ int64 │ string │ string │ string │ string │ string │ string │ string │ string │ string │ string │ string │
├────────────────┼─────────────────────────┼──────────────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼───────┼────────┼────────┼────────┼────────┼────────┼────────┼────────┼────────┼────────┼────────┼────────┤
│ 2 Pac          │ Baby Don't Cry (Keep... │ 2000-02-26   │    87 │    82 │    72 │    77 │    87 │    94 │    99 │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │
│ 2Ge+her        │ The Hardest Part Of ... │ 2000-09-02   │    91 │    87 │    92 │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │
│ 3 Doors Down   │ Kryptonite              │ 2000-04-08   │    81 │    70 │    68 │    67 │    66 │    57 │    54 │    53 │    51 │    51 │    51 │    51 │    47 │    44 │    38 │    28 │    22 │    18 │    18 │    14 │    12 │     7 │     6 │     6 │     6 │     5 │     5 │     4 │     4 │     4 │     4 │     3 │     3 │     3 │     4 │     5 │     5 │     9 │     9 │    15 │    14 │    13 │    14 │    16 │    17 │    21 │    22 │    24 │    28 │    33 │    42 │    42 │    49 │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │
│ 3 Doors Down   │ Loser                   │ 2000-10-21   │    76 │    76 │    72 │    69 │    67 │    65 │    55 │    59 │    62 │    61 │    61 │    59 │    61 │    66 │    72 │    76 │    75 │    67 │    73 │    70 │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │
│ 504 Boyz       │ Wobble Wobble           │ 2000-04-15   │    57 │    34 │    25 │    17 │    17 │    31 │    36 │    49 │    53 │    57 │    64 │    70 │    75 │    76 │    78 │    85 │    92 │    96 │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │
│ 98^0           │ Give Me Just One Nig... │ 2000-08-19   │    51 │    39 │    34 │    26 │    26 │    19 │     2 │     2 │     3 │     6 │     7 │    22 │    29 │    36 │    47 │    67 │    66 │    84 │    93 │    94 │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │
│ A*Teens        │ Dancing Queen           │ 2000-07-08   │    97 │    97 │    96 │    95 │   100 │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │
│ Aaliyah        │ I Don't Wanna           │ 2000-01-29   │    84 │    62 │    51 │    41 │    38 │    35 │    35 │    38 │    38 │    36 │    37 │    37 │    38 │    49 │    61 │    63 │    62 │    67 │    83 │    86 │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │
│ Aaliyah        │ Try Again               │ 2000-03-18   │    59 │    53 │    38 │    28 │    21 │    18 │    16 │    14 │    12 │    10 │     9 │     8 │     6 │     1 │     2 │     2 │     2 │     2 │     3 │     4 │     5 │     5 │     6 │     9 │    13 │    14 │    16 │    23 │    22 │    33 │    36 │    43 │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │
│ Adams, Yolanda │ Open My Heart           │ 2000-08-26   │    76 │    76 │    74 │    69 │    68 │    67 │    61 │    58 │    57 │    59 │    66 │    68 │    61 │    67 │    59 │    63 │    67 │    71 │    79 │    89 │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │  NULL │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │ NULL   │
│ …              │ …                       │ …            │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │     … │ …      │ …      │ …      │ …      │ …      │ …      │ …      │ …      │ …      │ …      │ …      │
└────────────────┴─────────────────────────┴──────────────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴───────┴────────┴────────┴────────┴────────┴────────┴────────┴────────┴────────┴────────┴────────┴────────┘

>>> billboard.pivot_longer(
...     s.startswith("wk"),
...     names_to="week",
...     names_pattern=r"wk(.+)",
...     names_transform=int,
...     values_to="rank",
...     values_transform=_.cast("int"),
... ).drop_null("rank")

┏━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━┳━━━━━━━┓
┃ artist  ┃ track                   ┃ date_entered ┃ week ┃ rank  ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━╇━━━━━━━┩
│ string  │ string                  │ date         │ int8 │ int64 │
├─────────┼─────────────────────────┼──────────────┼──────┼───────┤
│ 2 Pac   │ Baby Don't Cry (Keep... │ 2000-02-26   │    1 │    87 │
│ 2 Pac   │ Baby Don't Cry (Keep... │ 2000-02-26   │    2 │    82 │
│ 2 Pac   │ Baby Don't Cry (Keep... │ 2000-02-26   │    3 │    72 │
│ 2 Pac   │ Baby Don't Cry (Keep... │ 2000-02-26   │    4 │    77 │
│ 2 Pac   │ Baby Don't Cry (Keep... │ 2000-02-26   │    5 │    87 │
│ 2 Pac   │ Baby Don't Cry (Keep... │ 2000-02-26   │    6 │    94 │
│ 2 Pac   │ Baby Don't Cry (Keep... │ 2000-02-26   │    7 │    99 │
│ 2Ge+her │ The Hardest Part Of ... │ 2000-09-02   │    1 │    91 │
│ 2Ge+her │ The Hardest Part Of ... │ 2000-09-02   │    2 │    87 │
│ 2Ge+her │ The Hardest Part Of ... │ 2000-09-02   │    3 │    92 │
│ …       │ …                       │ …            │    … │     … │
└─────────┴─────────────────────────┴──────────────┴──────┴───────┘

You can use regular expression capture groups to extract multiple variables stored in column names

>>> who = ibis.examples.who.fetch()
>>> who

┏━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━┓
┃ country     ┃ iso2   ┃ iso3   ┃ year  ┃ new_sp_m014 ┃ new_sp_m1524 ┃ new_sp_m2534 ┃ new_sp_m3544 ┃ new_sp_m4554 ┃ new_sp_m5564 ┃ new_sp_m65 ┃ new_sp_f014 ┃ new_sp_f1524 ┃ new_sp_f2534 ┃ new_sp_f3544 ┃ new_sp_f4554 ┃ new_sp_f5564 ┃ new_sp_f65 ┃ new_sn_m014 ┃ new_sn_m1524 ┃ new_sn_m2534 ┃ new_sn_m3544 ┃ new_sn_m4554 ┃ new_sn_m5564 ┃ new_sn_m65 ┃ new_sn_f014 ┃ new_sn_f1524 ┃ new_sn_f2534 ┃ new_sn_f3544 ┃ new_sn_f4554 ┃ new_sn_f5564 ┃ new_sn_f65 ┃ new_ep_m014 ┃ new_ep_m1524 ┃ new_ep_m2534 ┃ new_ep_m3544 ┃ new_ep_m4554 ┃ new_ep_m5564 ┃ new_ep_m65 ┃ new_ep_f014 ┃ new_ep_f1524 ┃ new_ep_f2534 ┃ new_ep_f3544 ┃ new_ep_f4554 ┃ new_ep_f5564 ┃ new_ep_f65 ┃ newrel_m014 ┃ newrel_m1524 ┃ newrel_m2534 ┃ newrel_m3544 ┃ newrel_m4554 ┃ newrel_m5564 ┃ newrel_m65 ┃ newrel_f014 ┃ newrel_f1524 ┃ newrel_f2534 ┃ newrel_f3544 ┃ newrel_f4554 ┃ newrel_f5564 ┃ newrel_f65 ┃
┡━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━┩
│ string      │ string │ string │ int64 │ int64       │ int64        │ int64        │ int64        │ int64        │ int64        │ int64      │ int64       │ int64        │ int64        │ int64        │ int64        │ int64        │ int64      │ int64       │ int64        │ int64        │ int64        │ int64        │ int64        │ int64      │ int64       │ int64        │ int64        │ int64        │ int64        │ int64        │ int64      │ int64       │ int64        │ int64        │ int64        │ int64        │ int64        │ int64      │ int64       │ int64        │ int64        │ int64        │ int64        │ int64        │ int64      │ int64       │ int64        │ int64        │ int64        │ int64        │ int64        │ int64      │ int64       │ int64        │ int64        │ int64        │ int64        │ int64        │ int64      │
├─────────────┼────────┼────────┼───────┼─────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼────────────┼─────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼────────────┼─────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼────────────┼─────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼────────────┼─────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼────────────┼─────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼────────────┼─────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼────────────┼─────────────┼──────────────┼──────────────┼──────────────┼──────────────┼──────────────┼────────────┤
│ Afghanistan │ AF     │ AFG    │  1980 │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │
│ Afghanistan │ AF     │ AFG    │  1981 │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │
│ Afghanistan │ AF     │ AFG    │  1982 │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │
│ Afghanistan │ AF     │ AFG    │  1983 │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │
│ Afghanistan │ AF     │ AFG    │  1984 │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │
│ Afghanistan │ AF     │ AFG    │  1985 │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │
│ Afghanistan │ AF     │ AFG    │  1986 │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │
│ Afghanistan │ AF     │ AFG    │  1987 │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │
│ Afghanistan │ AF     │ AFG    │  1988 │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │
│ Afghanistan │ AF     │ AFG    │  1989 │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │        NULL │         NULL │         NULL │         NULL │         NULL │         NULL │       NULL │
│ …           │ …      │ …      │     … │           … │            … │            … │            … │            … │            … │          … │           … │            … │            … │            … │            … │            … │          … │           … │            … │            … │            … │            … │            … │          … │           … │            … │            … │            … │            … │            … │          … │           … │            … │            … │            … │            … │            … │          … │           … │            … │            … │            … │            … │            … │          … │           … │            … │            … │            … │            … │            … │          … │           … │            … │            … │            … │            … │            … │          … │
└─────────────┴────────┴────────┴───────┴─────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴────────────┴─────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴────────────┴─────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴────────────┴─────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴────────────┴─────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴────────────┴─────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴────────────┴─────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴────────────┴─────────────┴──────────────┴──────────────┴──────────────┴──────────────┴──────────────┴────────────┘

>>> len(who.columns)

>>> who.pivot_longer(
...     s.index["new_sp_m014":"newrel_f65"],
...     names_to=["diagnosis", "gender", "age"],
...     names_pattern="new_?(.*)_(.)(.*)",
...     values_to="count",
... )

┏━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ country     ┃ iso2   ┃ iso3   ┃ year  ┃ diagnosis ┃ gender ┃ age    ┃ count ┃
┡━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string      │ string │ string │ int64 │ string    │ string │ string │ int64 │
├─────────────┼────────┼────────┼───────┼───────────┼────────┼────────┼───────┤
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │ m      │ 014    │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │ m      │ 1524   │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │ m      │ 2534   │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │ m      │ 3544   │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │ m      │ 4554   │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │ m      │ 5564   │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │ m      │ 65     │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │ f      │ 014    │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │ f      │ 1524   │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │ f      │ 2534   │  NULL │
│ …           │ …      │ …      │     … │ …         │ …      │ …      │     … │
└─────────────┴────────┴────────┴───────┴───────────┴────────┴────────┴───────┘

names_transform is flexible, and can be:

1. A mapping of one or more names in `names_to` to callable
2. A callable that will be applied to every name

Let’s recode gender and age to numeric values using a mapping

>>> who.pivot_longer(
...     s.index["new_sp_m014":"newrel_f65"],
...     names_to=["diagnosis", "gender", "age"],
...     names_pattern="new_?(.*)_(.)(.*)",
...     names_transform=dict(
...         gender={"m": 1, "f": 2}.get,
...         age=dict(
...             zip(
...                 ["014", "1524", "2534", "3544", "4554", "5564", "65"],
...                 range(7),
...             )
...         ).get,
...     ),
...     values_to="count",
... )

┏━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━┳━━━━━━┳━━━━━━━┓
┃ country     ┃ iso2   ┃ iso3   ┃ year  ┃ diagnosis ┃ gender ┃ age  ┃ count ┃
┡━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━╇━━━━━━╇━━━━━━━┩
│ string      │ string │ string │ int64 │ string    │ int8   │ int8 │ int64 │
├─────────────┼────────┼────────┼───────┼───────────┼────────┼──────┼───────┤
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │      1 │    0 │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │      1 │    1 │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │      1 │    2 │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │      1 │    3 │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │      1 │    4 │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │      1 │    5 │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │      1 │    6 │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │      2 │    0 │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │      2 │    1 │  NULL │
│ Afghanistan │ AF     │ AFG    │  1980 │ sp        │      2 │    2 │  NULL │
│ …           │ …      │ …      │     … │ …         │      … │    … │     … │
└─────────────┴────────┴────────┴───────┴───────────┴────────┴──────┴───────┘

The number of match groups in names_pattern must match the length of names_to

>>> who.pivot_longer(  
...     s.index["new_sp_m014":"newrel_f65"],
...     names_to=["diagnosis", "gender", "age"],
...     names_pattern="new_?(.*)_.(.*)",
... )

---------------------------------------------------------------------------
IbisInputError                            Traceback (most recent call last)
Cell In[323], line 1
----> 1 who.pivot_longer(  
      2     s.index["new_sp_m014":"newrel_f65"],
      3     names_to=["diagnosis", "gender", "age"],
      4     names_pattern="new_?(.*)_.(.*)",
      5 )

File ~/work/ibis/ibis/ibis/expr/types/relations.py:3939, in Table.pivot_longer(self, col, names_to, names_pattern, names_transform, values_to, values_transform)
   3937 names_pattern = re.compile(names_pattern)
   3938 if (ngroups := names_pattern.groups) != (nnames := len(names_to)):
-> 3939     raise com.IbisInputError(
   3940         f"Number of match groups in `names_pattern`"
   3941         f"{names_pattern.pattern!r} ({ngroups:d} groups) doesn't "
   3942         f"match the length of `names_to` {names_to} (length {nnames:d})"
   3943     )
   3945 if names_transform is None:
   3946     names_transform = dict.fromkeys(names_to, toolz.identity)

IbisInputError: Number of match groups in `names_pattern`'new_?(.*)_.(.*)' (2 groups) doesn't match the length of `names_to` ['diagnosis', 'gender', 'age'] (length 3)

names_transform must be a mapping or callable

>>> who.pivot_longer(
...     s.index["new_sp_m014":"newrel_f65"], names_transform="upper"
... )  # quartodoc: +EXPECTED_FAILURE

---------------------------------------------------------------------------
IbisTypeError                             Traceback (most recent call last)
Cell In[326], line 1
----> 1 who.pivot_longer(
      2     s.index["new_sp_m014":"newrel_f65"], names_transform="upper"
      3 )  # quartodoc: +EXPECTED_FAILURE

File ~/work/ibis/ibis/ibis/expr/types/relations.py:3951, in Table.pivot_longer(self, col, names_to, names_pattern, names_transform, values_to, values_transform)
   3949         names_transform = dict.fromkeys(names_to, names_transform)
   3950     else:
-> 3951         raise com.IbisTypeError(
   3952             f"`names_transform` must be a mapping or callable. Got {type(names_transform)}"
   3953         )
   3955 for name in names_to:
   3956     names_transform.setdefault(name, toolz.identity)

IbisTypeError: `names_transform` must be a mapping or callable. Got <class 'str'>

pivot_wider

pivot_wider(
    id_cols=None,
    names_from='name',
    names_prefix='',
    names_sep='_',
    names_sort=False,
    names=None,
    values_from='value',
    values_fill=None,
    values_agg='arbitrary',
)

Pivot a table to a wider format.

Parameters

Name	Type	Description	Default
id_cols	`s`.`Selector` \| None	A set of columns that uniquely identify each observation.	`None`
names_from	str \| Iterable[str] \| `s`.`Selector`	An argument describing which column or columns to use to get the name of the output columns.	`'name'`
names_prefix	str	String added to the start of every column name.	`''`
names_sep	str	If `names_from` or `values_from` contains multiple columns, this argument will be used to join their values together into a single string to use as a column name.	`'_'`
names_sort	bool	If `True` columns are sorted. If `False` column names are ordered by appearance.	`False`
names	Iterable[str] \| None	An explicit sequence of values to look for in columns matching `names_from`. * When this value is `None`, the values will be computed from `names_from`. * When this value is not `None`, each element’s length must match the length of `names_from`. See examples below for more detail.	`None`
values_from	str \| Iterable[str] \| `s`.`Selector`	An argument describing which column or columns to get the cell values from.	`'value'`
values_fill	int \| float \| str \| `ir`.`Scalar` \| None	A scalar value that specifies what each value should be filled with when missing.	`None`
values_agg	str \| Callable[[`ir`.`Value`], `ir`.`Scalar`] \| Deferred	A function applied to the value in each cell in the output.	`'arbitrary'`

Returns

Name	Type	Description
	Table	Wider pivoted table

Examples

>>> import ibis
>>> import ibis.selectors as s
>>> from ibis import _
>>> ibis.options.interactive = True

Basic usage

>>> fish_encounters = ibis.examples.fish_encounters.fetch()
>>> fish_encounters

┏━━━━━━━┳━━━━━━━━━┳━━━━━━━┓
┃ fish  ┃ station ┃ seen  ┃
┡━━━━━━━╇━━━━━━━━━╇━━━━━━━┩
│ int64 │ string  │ int64 │
├───────┼─────────┼───────┤
│  4842 │ Release │     1 │
│  4842 │ I80_1   │     1 │
│  4842 │ Lisbon  │     1 │
│  4842 │ Rstr    │     1 │
│  4842 │ Base_TD │     1 │
│  4842 │ BCE     │     1 │
│  4842 │ BCW     │     1 │
│  4842 │ BCE2    │     1 │
│  4842 │ BCW2    │     1 │
│  4842 │ MAE     │     1 │
│     … │ …       │     … │
└───────┴─────────┴───────┘

>>> fish_encounters.pivot_wider(names_from="station", values_from="seen")

┏━━━━━━━┳━━━━━━━━┳━━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┓
┃ fish  ┃ Lisbon ┃ Base_TD ┃ MAE   ┃ MAW   ┃ Rstr  ┃ BCW   ┃ BCW2  ┃ Release ┃ I80_1 ┃ BCE   ┃ BCE2  ┃
┡━━━━━━━╇━━━━━━━━╇━━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━┩
│ int64 │ int64  │ int64   │ int64 │ int64 │ int64 │ int64 │ int64 │ int64   │ int64 │ int64 │ int64 │
├───────┼────────┼─────────┼───────┼───────┼───────┼───────┼───────┼─────────┼───────┼───────┼───────┤
│  4843 │      1 │       1 │     1 │     1 │     1 │     1 │     1 │       1 │     1 │     1 │     1 │
│  4848 │      1 │    NULL │  NULL │  NULL │     1 │  NULL │  NULL │       1 │     1 │  NULL │  NULL │
│  4865 │      1 │    NULL │  NULL │  NULL │  NULL │  NULL │  NULL │       1 │     1 │  NULL │  NULL │
│  4844 │      1 │       1 │     1 │     1 │     1 │     1 │     1 │       1 │     1 │     1 │     1 │
│  4845 │      1 │       1 │  NULL │  NULL │     1 │  NULL │  NULL │       1 │     1 │  NULL │  NULL │
│  4849 │   NULL │    NULL │  NULL │  NULL │  NULL │  NULL │  NULL │       1 │     1 │  NULL │  NULL │
│  4859 │      1 │       1 │  NULL │  NULL │     1 │  NULL │  NULL │       1 │     1 │  NULL │  NULL │
│  4861 │      1 │       1 │     1 │     1 │     1 │     1 │     1 │       1 │     1 │     1 │     1 │
│  4842 │      1 │       1 │     1 │     1 │     1 │     1 │     1 │       1 │     1 │     1 │     1 │
│  4847 │      1 │    NULL │  NULL │  NULL │  NULL │  NULL │  NULL │       1 │     1 │  NULL │  NULL │
│     … │      … │       … │     … │     … │     … │     … │     … │       … │     … │     … │     … │
└───────┴────────┴─────────┴───────┴───────┴───────┴───────┴───────┴─────────┴───────┴───────┴───────┘

You can do simple transpose-like operations using pivot_wider

>>> t = ibis.memtable(dict(outcome=["yes", "no"], counted=[3, 4]))
>>> t

┏━━━━━━━━━┳━━━━━━━━━┓
┃ outcome ┃ counted ┃
┡━━━━━━━━━╇━━━━━━━━━┩
│ string  │ int64   │
├─────────┼─────────┤
│ yes     │       3 │
│ no      │       4 │
└─────────┴─────────┘

>>> t.pivot_wider(names_from="outcome", values_from="counted", names_sort=True)

┏━━━━━━━┳━━━━━━━┓
┃ no    ┃ yes   ┃
┡━━━━━━━╇━━━━━━━┩
│ int64 │ int64 │
├───────┼───────┤
│     4 │     3 │
└───────┴───────┘

Fill missing pivoted values using values_fill

>>> fish_encounters.pivot_wider(
...     names_from="station", values_from="seen", values_fill=0
... )

┏━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━━┳━━━━━━━┓
┃ fish  ┃ Rstr  ┃ BCW   ┃ BCW2  ┃ Release ┃ I80_1 ┃ BCE   ┃ BCE2  ┃ MAW   ┃ Lisbon ┃ Base_TD ┃ MAE   ┃
┡━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━━╇━━━━━━━┩
│ int64 │ int64 │ int64 │ int64 │ int64   │ int64 │ int64 │ int64 │ int64 │ int64  │ int64   │ int64 │
├───────┼───────┼───────┼───────┼─────────┼───────┼───────┼───────┼───────┼────────┼─────────┼───────┤
│  4851 │     0 │     0 │     0 │       1 │     1 │     0 │     0 │     0 │      0 │       0 │     0 │
│  4857 │     1 │     1 │     1 │       1 │     1 │     1 │     1 │     0 │      1 │       1 │     0 │
│  4858 │     1 │     1 │     1 │       1 │     1 │     1 │     1 │     1 │      1 │       1 │     1 │
│  4862 │     1 │     1 │     1 │       1 │     1 │     1 │     1 │     0 │      1 │       1 │     0 │
│  4863 │     0 │     0 │     0 │       1 │     1 │     0 │     0 │     0 │      0 │       0 │     0 │
│  4843 │     1 │     1 │     1 │       1 │     1 │     1 │     1 │     1 │      1 │       1 │     1 │
│  4848 │     1 │     0 │     0 │       1 │     1 │     0 │     0 │     0 │      1 │       0 │     0 │
│  4865 │     0 │     0 │     0 │       1 │     1 │     0 │     0 │     0 │      1 │       0 │     0 │
│  4844 │     1 │     1 │     1 │       1 │     1 │     1 │     1 │     1 │      1 │       1 │     1 │
│  4845 │     1 │     0 │     0 │       1 │     1 │     0 │     0 │     0 │      1 │       1 │     0 │
│     … │     … │     … │     … │       … │     … │     … │     … │     … │      … │       … │     … │
└───────┴───────┴───────┴───────┴─────────┴───────┴───────┴───────┴───────┴────────┴─────────┴───────┘

Compute multiple values columns

>>> us_rent_income = ibis.examples.us_rent_income.fetch()
>>> us_rent_income

┏━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━┓
┃ geoid  ┃ name       ┃ variable ┃ estimate ┃ moe   ┃
┡━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━┩
│ string │ string     │ string   │ int64    │ int64 │
├────────┼────────────┼──────────┼──────────┼───────┤
│ 01     │ Alabama    │ income   │    24476 │   136 │
│ 01     │ Alabama    │ rent     │      747 │     3 │
│ 02     │ Alaska     │ income   │    32940 │   508 │
│ 02     │ Alaska     │ rent     │     1200 │    13 │
│ 04     │ Arizona    │ income   │    27517 │   148 │
│ 04     │ Arizona    │ rent     │      972 │     4 │
│ 05     │ Arkansas   │ income   │    23789 │   165 │
│ 05     │ Arkansas   │ rent     │      709 │     5 │
│ 06     │ California │ income   │    29454 │   109 │
│ 06     │ California │ rent     │     1358 │     3 │
│ …      │ …          │ …        │        … │     … │
└────────┴────────────┴──────────┴──────────┴───────┘

>>> us_rent_income.pivot_wider(
...     names_from="variable", values_from=["estimate", "moe"]
... )

┏━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━┓
┃ geoid  ┃ name         ┃ estimate_income ┃ moe_income ┃ estimate_rent ┃ moe_rent ┃
┡━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━┩
│ string │ string       │ int64           │ int64      │ int64         │ int64    │
├────────┼──────────────┼─────────────────┼────────────┼───────────────┼──────────┤
│ 05     │ Arkansas     │           23789 │        165 │           709 │        5 │
│ 06     │ California   │           29454 │        109 │          1358 │        3 │
│ 13     │ Georgia      │           27024 │        106 │           927 │        3 │
│ 15     │ Hawaii       │           32453 │        218 │          1507 │       18 │
│ 16     │ Idaho        │           25298 │        208 │           792 │        7 │
│ 30     │ Montana      │           26249 │        206 │           751 │        9 │
│ 38     │ North Dakota │           32336 │        245 │           775 │        9 │
│ 39     │ Ohio         │           27435 │         94 │           764 │        2 │
│ 40     │ Oklahoma     │           26207 │        101 │           766 │        3 │
│ 47     │ Tennessee    │           25453 │        102 │           808 │        4 │
│ …      │ …            │               … │          … │             … │        … │
└────────┴──────────────┴─────────────────┴────────────┴───────────────┴──────────┘

The column name separator can be changed using the names_sep parameter

>>> us_rent_income.pivot_wider(
...     names_from="variable",
...     names_sep=".",
...     values_from=("estimate", "moe"),
... )

┏━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━┓
┃ geoid  ┃ name         ┃ estimate.income ┃ moe.income ┃ estimate.rent ┃ moe.rent ┃
┡━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━┩
│ string │ string       │ int64           │ int64      │ int64         │ int64    │
├────────┼──────────────┼─────────────────┼────────────┼───────────────┼──────────┤
│ 05     │ Arkansas     │           23789 │        165 │           709 │        5 │
│ 06     │ California   │           29454 │        109 │          1358 │        3 │
│ 13     │ Georgia      │           27024 │        106 │           927 │        3 │
│ 15     │ Hawaii       │           32453 │        218 │          1507 │       18 │
│ 16     │ Idaho        │           25298 │        208 │           792 │        7 │
│ 30     │ Montana      │           26249 │        206 │           751 │        9 │
│ 38     │ North Dakota │           32336 │        245 │           775 │        9 │
│ 39     │ Ohio         │           27435 │         94 │           764 │        2 │
│ 40     │ Oklahoma     │           26207 │        101 │           766 │        3 │
│ 47     │ Tennessee    │           25453 │        102 │           808 │        4 │
│ …      │ …            │               … │          … │             … │        … │
└────────┴──────────────┴─────────────────┴────────────┴───────────────┴──────────┘

Supply an alternative function to summarize values

>>> warpbreaks = ibis.examples.warpbreaks.fetch().select("wool", "tension", "breaks")
>>> warpbreaks

┏━━━━━━━━┳━━━━━━━━━┳━━━━━━━━┓
┃ wool   ┃ tension ┃ breaks ┃
┡━━━━━━━━╇━━━━━━━━━╇━━━━━━━━┩
│ string │ string  │ int64  │
├────────┼─────────┼────────┤
│ A      │ L       │     26 │
│ A      │ L       │     30 │
│ A      │ L       │     54 │
│ A      │ L       │     25 │
│ A      │ L       │     70 │
│ A      │ L       │     52 │
│ A      │ L       │     51 │
│ A      │ L       │     26 │
│ A      │ L       │     67 │
│ A      │ M       │     18 │
│ …      │ …       │      … │
└────────┴─────────┴────────┘

>>> warpbreaks.pivot_wider(
...     names_from="wool", values_from="breaks", values_agg="mean"
... ).select("tension", "A", "B").order_by("tension")

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━┓
┃ tension ┃ A         ┃ B         ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━┩
│ string  │ float64   │ float64   │
├─────────┼───────────┼───────────┤
│ H       │ 24.555556 │ 18.777778 │
│ L       │ 44.555556 │ 28.222222 │
│ M       │ 24.000000 │ 28.777778 │
└─────────┴───────────┴───────────┘

Passing Deferred objects to values_agg is supported

>>> warpbreaks.pivot_wider(
...     names_from="tension",
...     values_from="breaks",
...     values_agg=_.sum(),
... ).select("wool", "H", "L", "M").order_by(s.all())

┏━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┓
┃ wool   ┃ H     ┃ L     ┃ M     ┃
┡━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━┩
│ string │ int64 │ int64 │ int64 │
├────────┼───────┼───────┼───────┤
│ A      │   221 │   401 │   216 │
│ B      │   169 │   254 │   259 │
└────────┴───────┴───────┴───────┘

Use a custom aggregate function

>>> warpbreaks.pivot_wider(
...     names_from="wool",
...     values_from="breaks",
...     values_agg=lambda col: col.std() / col.mean(),
... ).select("tension", "A", "B").order_by("tension")

┏━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━┓
┃ tension ┃ A        ┃ B        ┃
┡━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━┩
│ string  │ float64  │ float64  │
├─────────┼──────────┼──────────┤
│ H       │ 0.418344 │ 0.260590 │
│ L       │ 0.406183 │ 0.349325 │
│ M       │ 0.360844 │ 0.327719 │
└─────────┴──────────┴──────────┘

Generate some random data, setting the random seed for reproducibility

>>> import random
>>> random.seed(0)
>>> raw = ibis.memtable(
...     [
...         dict(
...             product=product,
...             country=country,
...             year=year,
...             production=random.random(),
...         )
...         for product in "AB"
...         for country in ["AI", "EI"]
...         for year in range(2000, 2015)
...     ]
... )
>>> production = raw.filter(((_.product == "A") & (_.country == "AI")) | (_.product == "B"))
>>> production.order_by(s.all())

┏━━━━━━━━━┳━━━━━━━━━┳━━━━━━━┳━━━━━━━━━━━━┓
┃ product ┃ country ┃ year  ┃ production ┃
┡━━━━━━━━━╇━━━━━━━━━╇━━━━━━━╇━━━━━━━━━━━━┩
│ string  │ string  │ int64 │ float64    │
├─────────┼─────────┼───────┼────────────┤
│ A       │ AI      │  2000 │   0.844422 │
│ A       │ AI      │  2001 │   0.757954 │
│ A       │ AI      │  2002 │   0.420572 │
│ A       │ AI      │  2003 │   0.258917 │
│ A       │ AI      │  2004 │   0.511275 │
│ A       │ AI      │  2005 │   0.404934 │
│ A       │ AI      │  2006 │   0.783799 │
│ A       │ AI      │  2007 │   0.303313 │
│ A       │ AI      │  2008 │   0.476597 │
│ A       │ AI      │  2009 │   0.583382 │
│ …       │ …       │     … │          … │
└─────────┴─────────┴───────┴────────────┘

Pivoting with multiple name columns

>>> production.pivot_wider(
...     names_from=["product", "country"],
...     values_from="production",
... )

┏━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━┓
┃ year  ┃ A_AI     ┃ B_AI     ┃ B_EI     ┃
┡━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━┩
│ int64 │ float64  │ float64  │ float64  │
├───────┼──────────┼──────────┼──────────┤
│  2004 │ 0.511275 │ 0.548699 │ 0.967540 │
│  2006 │ 0.783799 │ 0.719705 │ 0.447970 │
│  2007 │ 0.303313 │ 0.398824 │ 0.080446 │
│  2008 │ 0.476597 │ 0.824845 │ 0.320055 │
│  2011 │ 0.504687 │ 0.493578 │ 0.109058 │
│  2002 │ 0.420572 │ 0.260492 │ 0.567511 │
│  2005 │ 0.404934 │ 0.014042 │ 0.803179 │
│  2001 │ 0.757954 │ 0.865310 │ 0.191067 │
│  2003 │ 0.258917 │ 0.805028 │ 0.238616 │
│  2009 │ 0.583382 │ 0.668153 │ 0.507941 │
│     … │        … │        … │        … │
└───────┴──────────┴──────────┴──────────┘

Select a subset of names. This call incurs no computation when constructing the expression.

>>> production.pivot_wider(
...     names_from=["product", "country"],
...     names=[("A", "AI"), ("B", "AI")],
...     values_from="production",
... )

┏━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━┓
┃ year  ┃ A_AI     ┃ B_AI     ┃
┡━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━┩
│ int64 │ float64  │ float64  │
├───────┼──────────┼──────────┤
│  2002 │ 0.420572 │ 0.260492 │
│  2005 │ 0.404934 │ 0.014042 │
│  2013 │ 0.755804 │ 0.243911 │
│  2001 │ 0.757954 │ 0.865310 │
│  2003 │ 0.258917 │ 0.805028 │
│  2009 │ 0.583382 │ 0.668153 │
│  2012 │ 0.281838 │ 0.867603 │
│  2004 │ 0.511275 │ 0.548699 │
│  2006 │ 0.783799 │ 0.719705 │
│  2007 │ 0.303313 │ 0.398824 │
│     … │        … │        … │
└───────┴──────────┴──────────┘

Sort the new columns’ names

>>> production.pivot_wider(
...     names_from=["product", "country"],
...     values_from="production",
...     names_sort=True,
... )

┏━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━┓
┃ year  ┃ A_AI     ┃ B_AI     ┃ B_EI     ┃
┡━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━┩
│ int64 │ float64  │ float64  │ float64  │
├───────┼──────────┼──────────┼──────────┤
│  2001 │ 0.757954 │ 0.865310 │ 0.191067 │
│  2003 │ 0.258917 │ 0.805028 │ 0.238616 │
│  2009 │ 0.583382 │ 0.668153 │ 0.507941 │
│  2012 │ 0.281838 │ 0.867603 │ 0.551267 │
│  2004 │ 0.511275 │ 0.548699 │ 0.967540 │
│  2006 │ 0.783799 │ 0.719705 │ 0.447970 │
│  2007 │ 0.303313 │ 0.398824 │ 0.080446 │
│  2008 │ 0.476597 │ 0.824845 │ 0.320055 │
│  2011 │ 0.504687 │ 0.493578 │ 0.109058 │
│  2000 │ 0.844422 │ 0.477010 │ 0.870471 │
│     … │        … │        … │        … │
└───────┴──────────┴──────────┴──────────┘

preview

preview(
    max_rows=None,
    max_columns=None,
    max_length=None,
    max_string=None,
    max_depth=None,
    console_width=None,
)

Return a subset as a Rich Table.

This is an explicit version of what you get when you inspect this object in interactive mode, except with this version you can pass formatting options. The options are the same as those exposed in ibis.options.interactive.

Parameters

Name	Type	Description	Default
max_rows	int \| None	Maximum number of rows to display	`None`
max_columns	int \| None	Maximum number of columns to display	`None`
max_length	int \| None	Maximum length for pretty-printed arrays and maps	`None`
max_string	int \| None	Maximum length for pretty-printed strings	`None`
max_depth	int \| None	Maximum depth for nested data types	`None`
console_width	int \| float \| None	Width of the console in characters. If not specified, the width will be inferred from the console.	`None`

Examples

>>> import ibis
>>> t = ibis.examples.penguins.fetch()

Because the console_width is too small, only 2 columns are shown even though we specified up to 3.

>>> t.preview(
...     max_rows=3,
...     max_columns=3,
...     max_string=8,
...     console_width=30,
... )

┏━━━━━━━━━┳━━━━━━━━━━┳━━━┓
┃ species ┃ island   ┃ … ┃
┡━━━━━━━━━╇━━━━━━━━━━╇━━━┩
│ string  │ string   │ … │
├─────────┼──────────┼───┤
│ Adelie  │ Torgers… │ … │
│ Adelie  │ Torgers… │ … │
│ Adelie  │ Torgers… │ … │
│ …       │ …        │ … │
└─────────┴──────────┴───┘

relabel

relabel(substitutions)

Deprecated in favor of Table.rename.

relocate

relocate(*columns, before=None, after=None, **kwargs)

Relocate columns before or after other specified columns.

Parameters

Name	Type	Description	Default
columns	str \| `s`.`Selector`	Columns to relocate. Selectors are accepted.	`()`
before	str \| `s`.`Selector` \| None	A column name or selector to insert the new columns before.	`None`
after	str \| `s`.`Selector` \| None	A column name or selector. Columns in `columns` are relocated after the last column selected in `after`.	`None`
kwargs	str	Additional column names to relocate, renaming argument values to keyword argument names.	`{}`

Returns

Name	Type	Description
	Table	A table with the columns relocated.

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> import ibis.selectors as s
>>> t = ibis.memtable(dict(a=[1], b=[1], c=[1], d=["a"], e=["a"], f=["a"]))
>>> t

┏━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┓
┃ a     ┃ b     ┃ c     ┃ d      ┃ e      ┃ f      ┃
┡━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━┩
│ int64 │ int64 │ int64 │ string │ string │ string │
├───────┼───────┼───────┼────────┼────────┼────────┤
│     1 │     1 │     1 │ a      │ a      │ a      │
└───────┴───────┴───────┴────────┴────────┴────────┘

>>> t.relocate("f")

┏━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━┓
┃ f      ┃ a     ┃ b     ┃ c     ┃ d      ┃ e      ┃
┡━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━┩
│ string │ int64 │ int64 │ int64 │ string │ string │
├────────┼───────┼───────┼───────┼────────┼────────┤
│ a      │     1 │     1 │     1 │ a      │ a      │
└────────┴───────┴───────┴───────┴────────┴────────┘

>>> t.relocate("a", after="c")

┏━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┓
┃ b     ┃ c     ┃ a     ┃ d      ┃ e      ┃ f      ┃
┡━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━┩
│ int64 │ int64 │ int64 │ string │ string │ string │
├───────┼───────┼───────┼────────┼────────┼────────┤
│     1 │     1 │     1 │ a      │ a      │ a      │
└───────┴───────┴───────┴────────┴────────┴────────┘

>>> t.relocate("f", before="b")

┏━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━┓
┃ a     ┃ f      ┃ b     ┃ c     ┃ d      ┃ e      ┃
┡━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━┩
│ int64 │ string │ int64 │ int64 │ string │ string │
├───────┼────────┼───────┼───────┼────────┼────────┤
│     1 │ a      │     1 │     1 │ a      │ a      │
└───────┴────────┴───────┴───────┴────────┴────────┘

>>> t.relocate("a", after=s.last())

┏━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ b     ┃ c     ┃ d      ┃ e      ┃ f      ┃ a     ┃
┡━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ int64 │ int64 │ string │ string │ string │ int64 │
├───────┼───────┼────────┼────────┼────────┼───────┤
│     1 │     1 │ a      │ a      │ a      │     1 │
└───────┴───────┴────────┴────────┴────────┴───────┘

Relocate allows renaming

>>> t.relocate(ff="f")

┏━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━┓
┃ ff     ┃ a     ┃ b     ┃ c     ┃ d      ┃ e      ┃
┡━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━┩
│ string │ int64 │ int64 │ int64 │ string │ string │
├────────┼───────┼───────┼───────┼────────┼────────┤
│ a      │     1 │     1 │     1 │ a      │ a      │
└────────┴───────┴───────┴───────┴────────┴────────┘

You can relocate based on any predicate selector, such as of_type

>>> t.relocate(s.of_type("string"))

┏━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┓
┃ d      ┃ e      ┃ f      ┃ a     ┃ b     ┃ c     ┃
┡━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━┩
│ string │ string │ string │ int64 │ int64 │ int64 │
├────────┼────────┼────────┼───────┼───────┼───────┤
│ a      │ a      │ a      │     1 │     1 │     1 │
└────────┴────────┴────────┴───────┴───────┴───────┘

>>> t.relocate(s.numeric(), after=s.last())

┏━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━┳━━━━━━━┓
┃ d      ┃ e      ┃ f      ┃ a     ┃ b     ┃ c     ┃
┡━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━╇━━━━━━━┩
│ string │ string │ string │ int64 │ int64 │ int64 │
├────────┼────────┼────────┼───────┼───────┼───────┤
│ a      │ a      │ a      │     1 │     1 │     1 │
└────────┴────────┴────────┴───────┴───────┴───────┘

When multiple columns are selected with before or after, those selected columns are moved before and after the selectors input

>>> t = ibis.memtable(dict(a=[1], b=["a"], c=[1], d=["a"]))
>>> t.relocate(s.numeric(), after=s.of_type("string"))

┏━━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━┓
┃ b      ┃ d      ┃ a     ┃ c     ┃
┡━━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━┩
│ string │ string │ int64 │ int64 │
├────────┼────────┼───────┼───────┤
│ a      │ a      │     1 │     1 │
└────────┴────────┴───────┴───────┘

>>> t.relocate(s.numeric(), before=s.of_type("string"))

┏━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━━┓
┃ a     ┃ c     ┃ b      ┃ d      ┃
┡━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━━┩
│ int64 │ int64 │ string │ string │
├───────┼───────┼────────┼────────┤
│     1 │     1 │ a      │ a      │
└───────┴───────┴────────┴────────┘

When there are duplicate renames in a call to relocate, the last one is preserved

>>> t.relocate(e="d", f="d")

┏━━━━━━━━┳━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ f      ┃ a     ┃ b      ┃ c     ┃
┡━━━━━━━━╇━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string │ int64 │ string │ int64 │
├────────┼───────┼────────┼───────┤
│ a      │     1 │ a      │     1 │
└────────┴───────┴────────┴───────┘

However, if there are duplicates that are not part of a rename, the order specified in the relocate call is preserved

>>> t.relocate(
...     "b",
...     s.of_type("string"),  # "b" is a string column, so the selector matches
... )

┏━━━━━━━━┳━━━━━━━━┳━━━━━━━┳━━━━━━━┓
┃ b      ┃ d      ┃ a     ┃ c     ┃
┡━━━━━━━━╇━━━━━━━━╇━━━━━━━╇━━━━━━━┩
│ string │ string │ int64 │ int64 │
├────────┼────────┼───────┼───────┤
│ a      │ a      │     1 │     1 │
└────────┴────────┴───────┴───────┘

rename

rename(method=None, /, **substitutions)

Rename columns in the table.

Parameters

Name	Type	Description	Default
method	str \| Callable[[str], str \| None] \| Literal['snake_case', 'ALL_CAPS'] \| Mapping[str, str] \| None	An optional method for renaming columns. May be one of: - A format string to use to rename all columns, like `"prefix_{name}"`. - A function from old name to new name. If the function returns `None` the old name is used. - The literal strings `"snake_case"` or `"ALL_CAPS"` to rename all columns using a `snake_case` or "ALL_CAPS"`` naming convention respectively. - A mapping from new name to old name. Existing columns not present in the mapping will passthrough with their original name. \|None`\| \| substitutions \| [str](`str`) \| Columns to be explicitly renamed, expressed as`new_name=old_name``keyword arguments. \|``

Returns

Name	Type	Description
	Table	A renamed table expression

Examples

>>> import ibis
>>> import ibis.selectors as s
>>> ibis.options.interactive = True
>>> first3 = s.index[:3]  # first 3 columns
>>> t = ibis.examples.penguins_raw_raw.fetch().select(first3)
>>> t

┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ studyName ┃ Sample Number ┃ Species                             ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ string    │ int64         │ string                              │
├───────────┼───────────────┼─────────────────────────────────────┤
│ PAL0708   │             1 │ Adelie Penguin (Pygoscelis adeliae) │
│ PAL0708   │             2 │ Adelie Penguin (Pygoscelis adeliae) │
│ PAL0708   │             3 │ Adelie Penguin (Pygoscelis adeliae) │
│ PAL0708   │             4 │ Adelie Penguin (Pygoscelis adeliae) │
│ PAL0708   │             5 │ Adelie Penguin (Pygoscelis adeliae) │
│ PAL0708   │             6 │ Adelie Penguin (Pygoscelis adeliae) │
│ PAL0708   │             7 │ Adelie Penguin (Pygoscelis adeliae) │
│ PAL0708   │             8 │ Adelie Penguin (Pygoscelis adeliae) │
│ PAL0708   │             9 │ Adelie Penguin (Pygoscelis adeliae) │
│ PAL0708   │            10 │ Adelie Penguin (Pygoscelis adeliae) │
│ …         │             … │ …                                   │
└───────────┴───────────────┴─────────────────────────────────────┘

Rename specific columns by passing keyword arguments like `new_name=“old_name”``

>>> t.rename(study_name="studyName").head(1)

┏━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ study_name ┃ Sample Number ┃ Species                             ┃
┡━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ string     │ int64         │ string                              │
├────────────┼───────────────┼─────────────────────────────────────┤
│ PAL0708    │             1 │ Adelie Penguin (Pygoscelis adeliae) │
└────────────┴───────────────┴─────────────────────────────────────┘

Rename all columns using a format string

>>> t.rename("p_{name}").head(1)

┏━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ p_studyName ┃ p_Sample Number ┃ p_Species                           ┃
┡━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ string      │ int64           │ string                              │
├─────────────┼─────────────────┼─────────────────────────────────────┤
│ PAL0708     │               1 │ Adelie Penguin (Pygoscelis adeliae) │
└─────────────┴─────────────────┴─────────────────────────────────────┘

Rename all columns using a snake_case convention

>>> t.rename("snake_case").head(1)

┏━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ study_name ┃ sample_number ┃ species                             ┃
┡━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ string     │ int64         │ string                              │
├────────────┼───────────────┼─────────────────────────────────────┤
│ PAL0708    │             1 │ Adelie Penguin (Pygoscelis adeliae) │
└────────────┴───────────────┴─────────────────────────────────────┘

Rename all columns using an ALL_CAPS convention

>>> t.rename("ALL_CAPS").head(1)

┏━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ STUDY_NAME ┃ SAMPLE_NUMBER ┃ SPECIES                             ┃
┡━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ string     │ int64         │ string                              │
├────────────┼───────────────┼─────────────────────────────────────┤
│ PAL0708    │             1 │ Adelie Penguin (Pygoscelis adeliae) │
└────────────┴───────────────┴─────────────────────────────────────┘

Rename all columns using a callable

>>> t.rename(str.upper).head(1)

┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ STUDYNAME ┃ SAMPLE NUMBER ┃ SPECIES                             ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ string    │ int64         │ string                              │
├───────────┼───────────────┼─────────────────────────────────────┤
│ PAL0708   │             1 │ Adelie Penguin (Pygoscelis adeliae) │
└───────────┴───────────────┴─────────────────────────────────────┘

rowid

rowid()

A unique integer per row.

This operation is only valid on physical tables

Any further meaning behind this expression is backend dependent. Generally this corresponds to some index into the database storage (for example, SQLite and DuckDB’s rowid).

For a monotonically increasing row number, see ibis.row_number.

Returns

Name	Type	Description
	IntegerColumn	An integer column

sample

sample(fraction, *, method='row', seed=None)

Sample a fraction of rows from a table.

Results may be non-repeatable

Sampling is by definition a random operation. Some backends support specifying a seed for repeatable results, but not all backends support that option. And some backends (duckdb, for example) do support specifying a seed but may still not have repeatable results in all cases.

In all cases, results are backend-specific. An execution against one backend is unlikely to sample the same rows when executed against a different backend, even with the same seed set.

Parameters

Name	Type	Description	Default
fraction	float	The percentage of rows to include in the sample, expressed as a float between 0 and 1.	required
method	Literal['row', 'block']	The sampling method to use. The default is “row”, which includes each row with a probability of `fraction`. If method is “block”, some backends may instead sample a fraction of blocks of rows (where “block” is a backend dependent definition), which may be significantly more efficient (at the cost of a less statistically random sample). This is identical to “row” for backends lacking a blockwise sampling implementation. For those coming from SQL, “row” and “block” correspond to “bernoulli” and “system” respectively in a TABLESAMPLE clause.	`'row'`
seed	int \| None	An optional random seed to use, for repeatable sampling. The range of possible seed values is backend specific (most support at least `[0, 2**31 - 1]`). Backends that never support specifying a seed for repeatable sampling will error appropriately. Note that some backends (like DuckDB) do support specifying a seed, but may still not have repeatable results in all cases.	`None`

Returns

Name	Type	Description
	Table	The input table, with `fraction` of rows selected.

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.memtable({"x": [1, 2, 3, 4], "y": ["a", "b", "c", "d"]})
>>> t

┏━━━━━━━┳━━━━━━━━┓
┃ x     ┃ y      ┃
┡━━━━━━━╇━━━━━━━━┩
│ int64 │ string │
├───────┼────────┤
│     1 │ a      │
│     2 │ b      │
│     3 │ c      │
│     4 │ d      │
└───────┴────────┘

Sample approximately half the rows, with a seed specified for reproducibility.

>>> t.sample(0.5, seed=1234)

┏━━━━━━━┳━━━━━━━━┓
┃ x     ┃ y      ┃
┡━━━━━━━╇━━━━━━━━┩
│ int64 │ string │
├───────┼────────┤
│     2 │ b      │
│     3 │ c      │
└───────┴────────┘

schema

schema()

Return the Schema for this table.

Returns

Name	Type	Description
	`Schema`	The table’s schema.

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> t.schema()

ibis.Schema {
  species            string
  island             string
  bill_length_mm     float64
  bill_depth_mm      float64
  flipper_length_mm  int64
  body_mass_g        int64
  sex                string
  year               int64
}

select

select(*exprs, **named_exprs)

Compute a new table expression using exprs and named_exprs.

Passing an aggregate function to this method will broadcast the aggregate’s value over the number of rows in the table and automatically constructs a window function expression. See the examples section for more details.

For backwards compatibility the keyword argument exprs is reserved and cannot be used to name an expression. This behavior will be removed in v4.

Parameters

Name	Type	Description	Default
exprs	`ir`.`Value` \| str \| Iterable[`ir`.`Value` \| str]	Column expression, string, or list of column expressions and strings.	`()`
named_exprs	`ir`.`Value` \| str	Column expressions	`{}`

Returns

Name	Type	Description
	Table	Table expression

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch()
>>> t

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
│ Adelie  │ Torgersen │           NULL │          NULL │              NULL │        NULL │ NULL   │  2007 │
│ Adelie  │ Torgersen │           36.7 │          19.3 │               193 │        3450 │ female │  2007 │
│ Adelie  │ Torgersen │           39.3 │          20.6 │               190 │        3650 │ male   │  2007 │
│ Adelie  │ Torgersen │           38.9 │          17.8 │               181 │        3625 │ female │  2007 │
│ Adelie  │ Torgersen │           39.2 │          19.6 │               195 │        4675 │ male   │  2007 │
│ Adelie  │ Torgersen │           34.1 │          18.1 │               193 │        3475 │ NULL   │  2007 │
│ Adelie  │ Torgersen │           42.0 │          20.2 │               190 │        4250 │ NULL   │  2007 │
│ …       │ …         │              … │             … │                 … │           … │ …      │     … │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

Simple projection

>>> t.select("island", "bill_length_mm").head()

┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓
┃ island    ┃ bill_length_mm ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━━┩
│ string    │ float64        │
├───────────┼────────────────┤
│ Torgersen │           39.1 │
│ Torgersen │           39.5 │
│ Torgersen │           40.3 │
│ Torgersen │           NULL │
│ Torgersen │           36.7 │
└───────────┴────────────────┘

In that simple case, you could also just use python’s indexing syntax

>>> t[["island", "bill_length_mm"]].head()

┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓
┃ island    ┃ bill_length_mm ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━━┩
│ string    │ float64        │
├───────────┼────────────────┤
│ Torgersen │           39.1 │
│ Torgersen │           39.5 │
│ Torgersen │           40.3 │
│ Torgersen │           NULL │
│ Torgersen │           36.7 │
└───────────┴────────────────┘

Projection by zero-indexed column position

>>> t.select(t[0], t[4]).head()

┏━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓
┃ species ┃ flipper_length_mm ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━┩
│ string  │ int64             │
├─────────┼───────────────────┤
│ Adelie  │               181 │
│ Adelie  │               186 │
│ Adelie  │               195 │
│ Adelie  │              NULL │
│ Adelie  │               193 │
└─────────┴───────────────────┘

Projection with renaming and compute in one call

>>> t.select(next_year=t.year + 1).head()

┏━━━━━━━━━━━┓
┃ next_year ┃
┡━━━━━━━━━━━┩
│ int64     │
├───────────┤
│      2008 │
│      2008 │
│      2008 │
│      2008 │
│      2008 │
└───────────┘

You can do the same thing with a named expression, and using the deferred API

>>> from ibis import _
>>> t.select((_.year + 1).name("next_year")).head()

┏━━━━━━━━━━━┓
┃ next_year ┃
┡━━━━━━━━━━━┩
│ int64     │
├───────────┤
│      2008 │
│      2008 │
│      2008 │
│      2008 │
│      2008 │
└───────────┘

Projection with aggregation expressions

>>> t.select("island", bill_mean=t.bill_length_mm.mean()).head()

┏━━━━━━━━━━━┳━━━━━━━━━━━┓
┃ island    ┃ bill_mean ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━┩
│ string    │ float64   │
├───────────┼───────────┤
│ Torgersen │  43.92193 │
│ Torgersen │  43.92193 │
│ Torgersen │  43.92193 │
│ Torgersen │  43.92193 │
│ Torgersen │  43.92193 │
└───────────┴───────────┘

Projection with a selector

>>> import ibis.selectors as s
>>> t.select(s.numeric() & ~s.cols("year")).head()

┏━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┓
┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃
┡━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━┩
│ float64        │ float64       │ int64             │ int64       │
├────────────────┼───────────────┼───────────────────┼─────────────┤
│           39.1 │          18.7 │               181 │        3750 │
│           39.5 │          17.4 │               186 │        3800 │
│           40.3 │          18.0 │               195 │        3250 │
│           NULL │          NULL │              NULL │        NULL │
│           36.7 │          19.3 │               193 │        3450 │
└────────────────┴───────────────┴───────────────────┴─────────────┘

Projection + aggregation across multiple columns

>>> from ibis import _
>>> t.select(s.across(s.numeric() & ~s.cols("year"), _.mean())).head()

┏━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┓
┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃
┡━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━┩
│ float64        │ float64       │ float64           │ float64     │
├────────────────┼───────────────┼───────────────────┼─────────────┤
│       43.92193 │      17.15117 │        200.915205 │ 4201.754386 │
│       43.92193 │      17.15117 │        200.915205 │ 4201.754386 │
│       43.92193 │      17.15117 │        200.915205 │ 4201.754386 │
│       43.92193 │      17.15117 │        200.915205 │ 4201.754386 │
│       43.92193 │      17.15117 │        200.915205 │ 4201.754386 │
└────────────────┴───────────────┴───────────────────┴─────────────┘

sql

sql(query, dialect=None)

Run a SQL query against a table expression.

Parameters

Name	Type	Description	Default
query	str	Query string	required
dialect	str \| None	Optional string indicating the dialect of `query`. Defaults to the backend’s native dialect.	`None`

Returns

Name	Type	Description
	Table	An opaque table expression

Examples

>>> import ibis
>>> from ibis import _
>>> ibis.options.interactive = True
>>> t = ibis.examples.penguins.fetch(table_name="penguins")
>>> expr = t.sql(
...     """
...     SELECT island, mean(bill_length_mm) AS avg_bill_length
...     FROM penguins
...     GROUP BY 1
...     ORDER BY 2 DESC
...     """
... )
>>> expr

┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┓
┃ island    ┃ avg_bill_length ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━┩
│ string    │ float64         │
├───────────┼─────────────────┤
│ Biscoe    │       45.257485 │
│ Dream     │       44.167742 │
│ Torgersen │       38.950980 │
└───────────┴─────────────────┘

Mix and match ibis expressions with SQL queries

>>> t = ibis.examples.penguins.fetch(table_name="penguins")
>>> expr = t.sql(
...     """
...     SELECT island, mean(bill_length_mm) AS avg_bill_length
...     FROM penguins
...     GROUP BY 1
...     ORDER BY 2 DESC
...     """
... )
>>> expr = expr.mutate(
...     island=_.island.lower(),
...     avg_bill_length=_.avg_bill_length.round(1),
... )
>>> expr

┏━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┓
┃ island    ┃ avg_bill_length ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━┩
│ string    │ float64         │
├───────────┼─────────────────┤
│ biscoe    │            45.3 │
│ dream     │            44.2 │
│ torgersen │            39.0 │
└───────────┴─────────────────┘

Because ibis expressions aren’t named, they aren’t visible to subsequent .sql calls. Use the alias method to assign a name to an expression.

>>> expr.alias("b").sql("SELECT * FROM b WHERE avg_bill_length > 40")

┏━━━━━━━━┳━━━━━━━━━━━━━━━━━┓
┃ island ┃ avg_bill_length ┃
┡━━━━━━━━╇━━━━━━━━━━━━━━━━━┩
│ string │ float64         │
├────────┼─────────────────┤
│ biscoe │            45.3 │
│ dream  │            44.2 │
└────────┴─────────────────┘

to_array

to_array()

Deprecated - use as_scalar instead.

to_csv

to_csv(path, *, params=None, **kwargs)

Write the results of executing the given expression to a CSV file.

This method is eager and will execute the associated expression immediately.

See https://arrow.apache.org/docs/python/generated/pyarrow.csv.CSVWriter.html for details.

Parameters

Name	Type	Description	Default
path	str \| Path	The data source. A string or Path to the CSV file.	required
params	Mapping[`ir`.`Scalar`, Any] \| None	Mapping of scalar parameter expressions to value.	`None`
**kwargs	Any	Additional keyword arguments passed to pyarrow.csv.CSVWriter	`{}`

to_delta

to_delta(path, *, params=None, **kwargs)

Write the results of executing the given expression to a Delta Lake table.

This method is eager and will execute the associated expression immediately.

Parameters

Name	Type	Description	Default
path	str \| Path	The data source. A string or Path to the Delta Lake table directory.	required
params	Mapping[`ir`.`Scalar`, Any] \| None	Mapping of scalar parameter expressions to value.	`None`
**kwargs	Any	Additional keyword arguments passed to deltalake.writer.write_deltalake method	`{}`

to_pandas

to_pandas(**kwargs)

Convert a table expression to a pandas DataFrame.

Parameters

Name	Type	Description	Default
kwargs		Same as keyword arguments to `execute`	`{}`

to_pandas_batches

to_pandas_batches(limit=None, params=None, chunk_size=1000000, **kwargs)

Execute expression and return an iterator of pandas DataFrames.

This method is eager and will execute the associated expression immediately.

Parameters

Name	Type	Description	Default
limit	int \| str \| None	An integer to effect a specific row limit. A value of `None` means “no limit”. The default is in `ibis/config.py`.	`None`
params	Mapping[`ir`.`Value`, Any] \| None	Mapping of scalar parameter expressions to value.	`None`
chunk_size	int	Maximum number of rows in each returned `DataFrame`.	`1000000`
kwargs	Any	Keyword arguments	`{}`

Returns

Name	Type	Description
	Iterator[pd.DataFrame]

to_parquet

to_parquet(path, *, params=None, **kwargs)

Write the results of executing the given expression to a parquet file.

This method is eager and will execute the associated expression immediately.

See https://arrow.apache.org/docs/python/generated/pyarrow.parquet.ParquetWriter.html for details.

Parameters

Name	Type	Description	Default
path	str \| Path	The data source. A string or Path to the parquet file.	required
params	Mapping[`ir`.`Scalar`, Any] \| None	Mapping of scalar parameter expressions to value.	`None`
**kwargs	Any	Additional keyword arguments passed to pyarrow.parquet.ParquetWriter	`{}`

Examples

Write out an expression to a single parquet file.

>>> import ibis
>>> import tempfile
>>> penguins = ibis.examples.penguins.fetch()
>>> penguins.to_parquet(tempfile.mktemp())

Partition on a single column.

>>> penguins.to_parquet(tempfile.mkdtemp(), partition_by="year")

Partition on multiple columns.

>>> penguins.to_parquet(tempfile.mkdtemp(), partition_by=("year", "island"))

Hive-partitioned output is currently only supported when using DuckDB

to_parquet_dir

to_parquet_dir(directory, *, params=None, **kwargs)

Write the results of executing the given expression to a parquet file in a directory.

This method is eager and will execute the associated expression immediately.

See https://arrow.apache.org/docs/python/generated/pyarrow.dataset.write_dataset.html for details.

Parameters

Name	Type	Description	Default
directory	str \| Path	The data target. A string or Path to the directory where the parquet file will be written.	required
params	Mapping[`ir`.`Scalar`, Any] \| None	Mapping of scalar parameter expressions to value.	`None`
**kwargs	Any	Additional keyword arguments passed to pyarrow.dataset.write_dataset	`{}`

to_polars

to_polars(params=None, limit=None, **kwargs)

Execute expression and return results as a polars dataframe.

This method is eager and will execute the associated expression immediately.

Parameters

Name	Type	Description	Default
params	Mapping[`ir`.`Scalar`, Any] \| None	Mapping of scalar parameter expressions to value.	`None`
limit	int \| str \| None	An integer to effect a specific row limit. A value of `None` means “no limit”. The default is in `ibis/config.py`.	`None`
kwargs	Any	Keyword arguments	`{}`

Returns

Name	Type	Description
	`DataFrame`	A polars dataframe holding the results of the executed expression.

to_pyarrow

to_pyarrow(params=None, limit=None, **kwargs)

Execute expression and return results in as a pyarrow table.

This method is eager and will execute the associated expression immediately.

Parameters

Name	Type	Description	Default
params	Mapping[`ir`.`Scalar`, Any] \| None	Mapping of scalar parameter expressions to value.	`None`
limit	int \| str \| None	An integer to effect a specific row limit. A value of `None` means “no limit”. The default is in `ibis/config.py`.	`None`
kwargs	Any	Keyword arguments	`{}`

Returns

Name	Type	Description
	`Table`	A pyarrow table holding the results of the executed expression.

to_pyarrow_batches

to_pyarrow_batches(limit=None, params=None, chunk_size=1000000, **kwargs)

Execute expression and return a RecordBatchReader.

This method is eager and will execute the associated expression immediately.

Parameters

Name	Type	Description	Default
limit	int \| str \| None	An integer to effect a specific row limit. A value of `None` means “no limit”. The default is in `ibis/config.py`.	`None`
params	Mapping[`ir`.`Value`, Any] \| None	Mapping of scalar parameter expressions to value.	`None`
chunk_size	int	Maximum number of rows in each returned record batch.	`1000000`
kwargs	Any	Keyword arguments	`{}`

Returns

Name	Type	Description
	`results`	RecordBatchReader

to_torch

to_torch(params=None, limit=None, **kwargs)

Execute an expression and return results as a dictionary of torch tensors.

Parameters

Name	Type	Description	Default
params	Mapping[`ir`.`Scalar`, Any] \| None	Parameters to substitute into the expression.	`None`
limit	int \| str \| None	An integer to effect a specific row limit. A value of `None` means no limit.	`None`
kwargs	Any	Keyword arguments passed into the backend’s `to_torch` implementation.	`{}`

Returns

Name	Type	Description
	dict[str, `torch`.`Tensor`]	A dictionary of torch tensors, keyed by column name.

try_cast

try_cast(schema)

Cast the columns of a table.

If the cast fails for a row, the value is returned as NULL or NaN depending on backend behavior.

Parameters

Name	Type	Description	Default
schema	`SchemaLike`	Mapping, schema or iterable of pairs to use for casting	required

Returns

Name	Type	Description
	Table	Casted table

Examples

>>> import ibis
>>> ibis.options.interactive = True
>>> t = ibis.memtable({"a": ["1", "2", "3"], "b": ["2.2", "3.3", "book"]})
>>> t.try_cast({"a": "int", "b": "float"})

┏━━━━━━━┳━━━━━━━━━┓
┃ a     ┃ b       ┃
┡━━━━━━━╇━━━━━━━━━┩
│ int64 │ float64 │
├───────┼─────────┤
│     1 │     2.2 │
│     2 │     3.3 │
│     3 │    NULL │
└───────┴─────────┘

unbind

unbind()

Return an expression built on UnboundTable instead of backend-specific objects.

Examples

>>> import ibis
>>> import pandas as pd

Table

Attributes

Methods

aggregate

Parameters

Returns

Examples

alias

Parameters

Returns

Examples

as_scalar

Returns

Examples

as_table

Returns

Examples

asof_join

Parameters

Returns

Examples

bind

Parameters

Returns

cache

Returns

Examples

cast

Parameters

Returns

Examples

compile

Parameters

Returns

Examples

See Also

count

Parameters

Returns

Examples

cross_join

Parameters

Returns

Examples

describe

Parameters

Returns

Notes

Examples

difference

Parameters

See Also

Returns

Examples

distinct

Parameters

Examples

drop

Parameters

Returns

Examples

drop_null

Parameters

Returns

Examples

dropna

equals

Parameters

Examples

execute

Parameters

Examples

See Also

fill_null

Parameters

Returns

Examples

fillna

filter

Parameters