pandas.Index.map — pandas 2.2.3 documentation (original) (raw)

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

Map values using an input mapping or function.

Parameters:

mapperfunction, 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')