pandas.CategoricalIndex.remove_unused_categories  
CategoricalIndex.remove_unused_categories(*args, **kwargs) [source]
 
Removes categories which are not used.    
Parameters:

inplace : boolean (default: False) Whether or not to drop unused categories inplace or return a copy of this categorical with unused categories dropped.   
Returns:

cat : Categorical with unused categories dropped or None if inplace.     See also rename_categories, reorder_categories, add_categories, remove_categories, set_categories  


    
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