diff --git a/pandas/core/indexes/multi.py b/pandas/core/indexes/multi.py index 05a4da28eb0a1..0908bc6209369 100644 --- a/pandas/core/indexes/multi.py +++ b/pandas/core/indexes/multi.py @@ -1,7 +1,7 @@ from collections import OrderedDict import datetime from sys import getsizeof -from typing import List, Optional +from typing import Hashable, List, Optional, Sequence, Union import warnings import numpy as np @@ -2430,7 +2430,53 @@ def reindex(self, target, method=None, level=None, limit=None, tolerance=None): return target, indexer - def get_slice_bound(self, label, side, kind): + def get_slice_bound( + self, label: Union[Hashable, Sequence[Hashable]], side: str, kind: str + ) -> int: + """ + For an ordered MultiIndex, compute slice bound + that corresponds to given label. + + Returns leftmost (one-past-the-rightmost if `side=='right') position + of given label. + + Parameters + ---------- + label : object or tuple of objects + side : {'left', 'right'} + kind : {'loc', 'getitem'} + + Returns + ------- + int + Index of label. + + Notes + ----- + This method only works if level 0 index of the MultiIndex is lexsorted. + + Examples + -------- + >>> mi = pd.MultiIndex.from_arrays([list('abbc'), list('gefd')]) + + Get the locations from the leftmost 'b' in the first level + until the end of the multiindex: + + >>> mi.get_slice_bound('b', side="left", kind="loc") + 1 + + Like above, but if you get the locations from the rightmost + 'b' in the first level and 'f' in the second level: + + >>> mi.get_slice_bound(('b','f'), side="right", kind="loc") + 3 + + See Also + -------- + MultiIndex.get_loc : Get location for a label or a tuple of labels. + MultiIndex.get_locs : Get location for a label/slice/list/mask or a + sequence of such. + """ if not isinstance(label, tuple): label = (label,)