Function _apply_indexes

xarray/core/indexes.py:2183–2204

(
    indexes: Indexes[Index],
    args: Mapping[Any, Any],
    func: str,
)

def _apply_indexes(
    indexes: Indexes[Index],
    args: Mapping[Any, Any],
    func: str,
) -> tuple[dict[Hashable, Index], dict[Hashable, Variable]]:
    new_indexes: dict[Hashable, Index] = dict(indexes.items())
    new_index_variables: dict[Hashable, Variable] = {}

    for index, index_vars in indexes.group_by_index():
        index_dims = {d for var in index_vars.values() for d in var.dims}
        index_args = {k: v for k, v in args.items() if k in index_dims}
        if index_args:
            new_index = getattr(index, func)(index_args)
            if new_index is not None:
                new_indexes.update(dict.fromkeys(index_vars, new_index))
                new_index_vars = new_index.create_variables(index_vars)
                new_index_variables.update(new_index_vars)
            else:
                for k in index_vars:
                    new_indexes.pop(k, None)

    return new_indexes, new_index_variables


def isel_indexes(