Method _wrap_applied_output

pandas/core/groupby/generic.py:538–608

Wrap the output of SeriesGroupBy.apply into the expected result. Parameters ---------- data : Series Input data for groupby operation. values : List[Any] Applied output for each group. not_indexed_same : bool, default False

(
        self,
        data: Series,
        values: list[Any],
        not_indexed_same: bool = False,
        is_transform: bool = False,
    )

        return output

    def _wrap_applied_output(
        self,
        data: Series,
        values: list[Any],
        not_indexed_same: bool = False,
        is_transform: bool = False,
    ) -> DataFrame | Series:
        """
        Wrap the output of SeriesGroupBy.apply into the expected result.

        Parameters
        ----------
        data : Series
            Input data for groupby operation.
        values : List[Any]
            Applied output for each group.
        not_indexed_same : bool, default False
            Whether the applied outputs are not indexed the same as the group axes.

        Returns
        -------
        DataFrame or Series
        """
        if len(values) == 0:
            # GH #6265
            if is_transform:
                # GH#47787 see test_group_on_empty_multiindex
                res_index = data.index
            elif not self.group_keys:
                res_index = None
            else:
                res_index = self._grouper.result_index

            return self.obj._constructor(
                [],
                name=self.obj.name,
                index=res_index,
                dtype=data.dtype,
            )
        assert values is not None

        if isinstance(values[0], dict):
            # GH #823 #24880
            index = self._grouper.result_index
            res_df = self.obj._constructor_expanddim(values, index=index)
            # if self.observed is False,
            # keep all-NaN rows created while re-indexing
            res_ser = res_df.stack()
            res_ser.name = self.obj.name
            return res_ser
        elif isinstance(values[0], (Series, DataFrame)):
            result = self._concat_objects(
                values,
                not_indexed_same=not_indexed_same,
                is_transform=is_transform,
            )
            if isinstance(result, Series):
                result.name = self.obj.name