Pandas Series: cat.rename_categories() function

Last update on September 15 2022 12:57:10 (UTC/GMT +8 hours)

Series-cat.rename_categories() function

The rename_categories() function is used to rename categories.

Syntax:

Series.cat.rename_categories(self, *args, **kwargs)

Parameters:

Name	Description	Type/Default Value	Required / Optional
new_categories	list-like: all items must be unique and the number of items in the new categories must match the existing number of categories. dict-like: specifies a mapping from old categories to new. callable : a callable that is called on all items in the old categories and whose return values comprise the new categories.	list-like, dict-like or callable	Required
inplace	Whether or not to rename the categories inplace or return a copy of this categorical with renamed categories.	bool, default False	Required

Returns: cat : Categorical or None

Raises: ValueError
If new categories are list-like and do not have the same number of items than the current categories or do not validate as categories

Example:

Python-Pandas Code:

import numpy as np
import pandas as pd
c = pd.Categorical(['p', 'p', 'q'])
c.rename_categories([0, 1])

Output:

[0, 0, 1]
Categories (2, int64): [0, 1]

Example - For dict-like new_categories, extra keys are ignored and categories not in the dictionary are passed through:

Python-Pandas Code:

import numpy as np
import pandas as pd
c = pd.Categorical(['p', 'p', 'q'])
c.rename_categories({'p': 'P', 'r': 'R'})

Output:

[P, P, q]
Categories (2, object): [P, q]

Example - You may also provide a callable to create the new categories:

Python-Pandas Code:

import numpy as np
import pandas as pd
c = pd.Categorical(['p', 'p', 'q'])
c.rename_categories(lambda x: x.upper())

Output:

[P, P, Q]
Categories (2, object): [P, Q]

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