pandas.Index.map

Index.map(mapper, na_action=None)[source]

Map values using an input mapping 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:

Union[Index, MultiIndex]

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.

Examples

>>> idx = pd.Index([1, 2, 3])
>>> idx.map({1: 'a', 2: 'b', 3: 'c'})
Index(['a', 'b', 'c'], dtype='object')

Using map with a function:

>>> idx = pd.Index([1, 2, 3])
>>> idx.map('I am a {}'.format)
Index(['I am a 1', 'I am a 2', 'I am a 3'], dtype='object')

>>> idx = pd.Index(['a', 'b', 'c'])
>>> idx.map(lambda x: x.upper())
Index(['A', 'B', 'C'], dtype='object')