polars.enable_string_cache#

polars.enable_string_cache(enable: bool | None = None) → None[source]#

Enable the global string cache.

Categorical columns created under the same global string cache have the same underlying physical value when string values are equal. This allows the columns to be concatenated or used in a join operation, for example.

Parameters:

enable: Enable or disable the global string cache.

Deprecated since version 0.19.3: enable_string_cache no longer accepts an argument. Call enable_string_cache() to enable the string cache and disable_string_cache() to disable the string cache.

See also

StringCache: Context manager for enabling and disabling the string cache.
disable_string_cache: Function to disable the string cache.

Notes

Enabling the global string cache introduces some overhead. The amount of overhead depends on the number of categories in your data. It is advised to enable the global string cache only when strictly necessary.

Consider using the StringCache context manager for a more reliable way of enabling and disabling the string cache.

Examples

Construct two Series using the same global string cache.

>>> pl.enable_string_cache()
>>> s1 = pl.Series("color", ["red", "green", "red"], dtype=pl.Categorical)
>>> s2 = pl.Series("color", ["blue", "red", "green"], dtype=pl.Categorical)
>>> pl.disable_string_cache()

As both Series are constructed under the same global string cache, they can be concatenated.

>>> pl.concat([s1, s2])
shape: (6,)
Series: 'color' [cat]
[
        "red"
        "green"
        "red"
        "blue"
        "red"
        "green"
]