pandas.Index.map

Index.map(self, mapper, na_action=None)

Map values using input correspondence (a dict, Series, or function).

Parameters:

mapper : function, dict, or Series

Mapping correspondence.

na_action : {None, ‘ignore’}

If ‘ignore’, propagate NA values, without passing them to the mapping correspondence.

Returns:

applied : Union[Index, MultiIndex], inferred

The output of the mapping function applied to the index. If the function returns a tuple with more than one element a MultiIndex will be returned.