polars.Series.cat.to_local

Series.cat.to_local() → Series

Convert a categorical column to its local representation.

This may change the underlying physical representation of the column.

See the documentation of StringCache() for more information on the difference between local and global categoricals.

Examples

Compare the global and local representations of a categorical.

>>> with pl.StringCache():
...     _ = pl.Series("x", ["a", "b", "a"], dtype=pl.Categorical)
...     s = pl.Series("y", ["c", "b", "d"], dtype=pl.Categorical)
...
>>> s.to_physical()
shape: (3,)
Series: 'y' [u32]
[
        2
        1
        3
]
>>> s.cat.to_local().to_physical()
shape: (3,)
Series: 'y' [u32]
[
        0
        1
        2
]