Class PandasIndex

xarray/core/indexes.py:651–965

Wrap a pandas.Index as an xarray compatible index.

class PandasIndex(Index):
    """Wrap a pandas.Index as an xarray compatible index."""

    index: pd.Index
    dim: Hashable
    coord_dtype: Any

    __slots__ = ("coord_dtype", "dim", "index")

    def __init__(
        self,
        array: Any,
        dim: Hashable,
        coord_dtype: Any = None,
        *,
        fastpath: bool = False,
    ):
        if fastpath:
            index = array
        else:
            index = safe_cast_to_index(array)

        if index.name is None:
            # make a shallow copy: cheap and because the index name may be updated
            # here or in other constructors (cannot use pd.Index.rename as this
            # constructor is also called from PandasMultiIndex)
            index = index.copy()
            index.name = dim

        self.index = index
        self.dim = dim
        if coord_dtype is None:
            if is_allowed_extension_array_dtype(index.dtype):
                cast(pd.api.extensions.ExtensionDtype, index.dtype)
                coord_dtype = index.dtype
            else:
                coord_dtype = get_valid_numpy_dtype(index)
        self.coord_dtype = coord_dtype

    def _replace(self, index, dim=None, coord_dtype=None):
        if dim is None:
            dim = self.dim
        if coord_dtype is None:
            coord_dtype = self.coord_dtype
        return type(self)(index, dim, coord_dtype, fastpath=True)

    @classmethod
    def from_variables(
        cls,
        variables: Mapping[Any, Variable],
        *,
        options: Mapping[str, Any],
    ) -> PandasIndex:
        if len(variables) != 1:
            raise ValueError(
                f"PandasIndex only accepts one variable, found {len(variables)} variables"
            )