Method reduce

xarray/core/dataset.py:6811–6932

Reduce this dataset by applying `func` along some dimension(s). Parameters ---------- func : callable Function which can be called in the form `f(x, axis=axis, **kwargs)` to return the result of reducing an np.ndarray over an integer value

(
        self,
        func: Callable,
        dim: Dims = None,
        *,
        keep_attrs: bool | None = None,
        keepdims: bool = False,
        numeric_only: bool = False,
        **kwargs: Any,
    )

        return out

    def reduce(
        self,
        func: Callable,
        dim: Dims = None,
        *,
        keep_attrs: bool | None = None,
        keepdims: bool = False,
        numeric_only: bool = False,
        **kwargs: Any,
    ) -> Self:
        """Reduce this dataset by applying `func` along some dimension(s).

        Parameters
        ----------
        func : callable
            Function which can be called in the form
            `f(x, axis=axis, **kwargs)` to return the result of reducing an
            np.ndarray over an integer valued axis.
        dim : str, Iterable of Hashable or None, optional
            Dimension(s) over which to apply `func`. By default `func` is
            applied over all dimensions.
        keep_attrs : bool or None, optional
            If True (default), the dataset's attributes (`attrs`) will be copied from
            the original object to the new one.  If False, the new
            object will be returned without attributes.
        keepdims : bool, default: False
            If True, the dimensions which are reduced are left in the result
            as dimensions of size one. Coordinates that use these dimensions
            are removed.
        numeric_only : bool, default: False
            If True, only apply ``func`` to variables with a numeric dtype.
        **kwargs : Any
            Additional keyword arguments passed on to ``func``.

        Returns
        -------
        reduced : Dataset
            Dataset with this object's DataArrays replaced with new DataArrays
            of summarized data and the indicated dimension(s) removed.

        Examples
        --------

        >>> dataset = xr.Dataset(
        ...     {
        ...         "math_scores": (
        ...             ["student", "test"],
        ...             [[90, 85, 92], [78, 80, 85], [95, 92, 98]],
        ...         ),
        ...         "english_scores": (
        ...             ["student", "test"],
        ...             [[88, 90, 92], [75, 82, 79], [93, 96, 91]],
        ...         ),
        ...     },
        ...     coords={
        ...         "student": ["Alice", "Bob", "Charlie"],
        ...         "test": ["Test 1", "Test 2", "Test 3"],
        ...     },