dask_expr._collection.Index.map
dask_expr._collection.Index.map¶
- Index.map(arg, na_action=None, meta=None, is_monotonic=False)[source]¶
Map values using an input mapping or function.
This docstring was copied from pandas.core.indexes.base.Index.map.
Some inconsistencies with the Dask version may exist.
Note that this method clears any known divisions.
If your mapping function is monotonically increasing then use is_monotonic to apply the maping function to the old divisions and assign the new divisions to the output.
- Parameters
- mapperfunction, dict, or Series (Not supported in Dask)
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')