pandas.CategoricalIndex.add_categories#

CategoricalIndex.add_categories(new_categories)[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_categoriescategory or list-like of category: The new categories to be included.

Returns:

CategoricalIndex: CategoricalIndex with new categories added.

Raises:

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

See also

CategoricalIndex.rename_categories: Rename categories.
CategoricalIndex.reorder_categories: Reorder categories.
CategoricalIndex.remove_categories: Remove the specified categories.
CategoricalIndex.remove_unused_categories: Remove categories which are not used.
CategoricalIndex.set_categories: Set the categories to the specified ones.

Examples

>>> ci = pd.CategoricalIndex(["c", "b", "c"])
>>> ci
CategoricalIndex(['c', 'b', 'c'], categories=['b', 'c'], ordered=False,
                 dtype='category')

>>> ci.add_categories(["d", "a"])
CategoricalIndex(['c', 'b', 'c'], categories=['b', 'c', 'd', 'a'],
                 ordered=False, dtype='category')