polars.apply¶
- polars.apply(exprs: List[Union[str, polars.internals.expr.Expr]], f: Callable[[List[polars.internals.series.Series]], Union[polars.internals.series.Series, Any]], return_dtype: Optional[Type[polars.datatypes.DataType]] = None) polars.internals.expr.Expr¶
Apply a custom function in a GroupBy context.
Depending on the context it has the following behavior:
## Context
- Select/Project
Don’t do this, use map
- GroupBy
expected type f: Callable[[Series], Series] Applies a python function over each group.
- Parameters
- exprs
Input Series to f
- f
Function to apply over the input
- return_dtype
dtype of the output Series
- Returns
- Expr