Method grouped_reduce

pandas/core/internals/managers.py:1645–1677

Apply grouped reduction function blockwise, returning a new BlockManager. Parameters ---------- func : grouped reduction function Returns ------- BlockManager

(self, func: Callable)

    # Block-wise Operation

    def grouped_reduce(self, func: Callable) -> Self:
        """
        Apply grouped reduction function blockwise, returning a new BlockManager.

        Parameters
        ----------
        func : grouped reduction function

        Returns
        -------
        BlockManager
        """
        result_blocks: list[Block] = []

        for blk in self.blocks:
            if blk.is_object:
                # split on object-dtype blocks bc some columns may raise
                #  while others do not.
                for sb in blk._split():
                    applied = sb.apply(func)
                    result_blocks = extend_blocks(applied, result_blocks)
            else:
                applied = blk.apply(func)
                result_blocks = extend_blocks(applied, result_blocks)

        if len(result_blocks) == 0:
            nrows = 0
        else:
            nrows = result_blocks[0].values.shape[-1]
        index = default_index(nrows)

        # TODO shallow copy columns?
        return type(self).from_blocks(result_blocks, [self.axes[0].view(), index])

    def reduce(self, func: Callable) -> Self:
        """