Source code for static_frame.core.hloc

from __future__ import annotations

import typing_extensions as tp

from static_frame.core.util import EMPTY_TUPLE, TLocSelector, key_to_str


class HLocMeta(type):
    def __getitem__(cls, key: TLocSelector) -> 'HLoc':
        if not isinstance(key, tuple) or key is EMPTY_TUPLE:
            key = (key,)
        return cls(key)  # type: ignore [no-any-return]




class HLoc(metaclass=HLocMeta):
    """
    A simple wrapper for embedding hierarchical specifications for :obj:`static_frame.IndexHierarchy` within a single axis argument of a ``loc`` selection.

    Implemented as a container of hierarchical keys that defines NULL slices for all lower dimensions that are not defined at construction.
    """

    STATIC = True
    __slots__ = ('key',)



    def __init__(self, key: tp.Tuple[TLocSelector]) -> None:
        self.key = key




    def __iter__(self) -> tp.Iterator[TLocSelector]:
        return self.key.__iter__()




    def __len__(self) -> int:
        return self.key.__len__()




    def __repr__(self) -> str:
        return f'<HLoc[{",".join(map(key_to_str, self.key))}]>'