pandas.CategoricalIndex.add_categories

CategoricalIndex.add_categories(*args, **kwargs)[source]

Add new categories.

new_categories will be included at the last/highest place in the categories and will be unused directly after this call.

Parameters

new_categories:category or list-like of category

The new categories to be included.

inplace:bool, default False

Whether or not to add the categories inplace or return a copy of this categorical with added categories.

Deprecated since version 1.3.0.

Returns

cat:Categorical or None

Categorical with new categories added or None if inplace=True.

Raises

ValueError

If the new categories include old categories or do not validate as categories

See also

rename_categories

Rename categories.

reorder_categories

Reorder categories.

remove_categories

Remove the specified categories.

remove_unused_categories

Remove categories which are not used.

set_categories

Set the categories to the specified ones.

Examples

>>> c = pd.Categorical(['c', 'b', 'c'])
>>> c
['c', 'b', 'c']
Categories (2, object): ['b', 'c']

>>> c.add_categories(['d', 'a'])
['c', 'b', 'c']
Categories (4, object): ['b', 'c', 'd', 'a']