Series.cat.
remove_categories
Remove the specified categories.
removals must be included in the old categories. Values which were in the removed categories will be set to NaN
The categories which should be removed.
Whether or not to remove the categories inplace or return a copy of this categorical with removed categories.
If the removals are not contained in the categories
See also
rename_categories
reorder_categories
add_categories
remove_unused_categories
set_categories