Function _normalize_indexes

xarray/structure/alignment.py:98–134

Normalize the indexes/indexers given for re-indexing or alignment. Wrap any arbitrary array or `pandas.Index` as an Xarray `PandasIndex` associated with its corresponding dimension coordinate variable.

(
    indexes: Mapping[Any, Any | T_DuckArray],
)

def _normalize_indexes(
    indexes: Mapping[Any, Any | T_DuckArray],
) -> Indexes:
    """Normalize the indexes/indexers given for re-indexing or alignment.

    Wrap any arbitrary array or `pandas.Index` as an Xarray `PandasIndex`
    associated with its corresponding dimension coordinate variable.

    """
    xr_indexes: dict[Hashable, Index] = {}
    xr_variables: dict[Hashable, Variable]

    if isinstance(indexes, Indexes):
        xr_variables = dict(indexes.variables)
    else:
        xr_variables = {}

    for k, idx in indexes.items():
        if not isinstance(idx, Index):
            if getattr(idx, "dims", (k,)) != (k,):
                raise AlignmentError(
                    f"Indexer has dimensions {idx.dims} that are different "
                    f"from that to be indexed along '{k}'"
                )
            data: T_DuckArray = as_compatible_data(idx)
            pd_idx = safe_cast_to_index(data)
            if pd_idx.name != k:
                pd_idx = pd_idx.copy()
                pd_idx.name = k
            if isinstance(pd_idx, pd.MultiIndex):
                idx = PandasMultiIndex(pd_idx, k)
            else:
                idx = PandasIndex(pd_idx, k, coord_dtype=data.dtype)
            xr_variables.update(idx.create_variables())
        xr_indexes[k] = idx

    return Indexes(xr_indexes, xr_variables)


CoordNamesAndDims = tuple[tuple[Hashable, tuple[Hashable, ...]], ...]