www.gusucode.com > matlab 案例源码 matlab代码程序 > matlab/RemoveAllUnusedCategoriesExample.m

    %% Remove All Unused Categories  

%% 
% Create a categorical array representing political parties of four people. 
A = categorical({'republican' 'democrat' 'democrat' 'republican'},...
    {'democrat' 'republican' 'independent'}) 

%%
% |A| is a 1-by-4 categorical array.  

%% 
% Summarize the categorical array, |A|. 
summary(A) 

%%
% |A| has three categories. |democrat| appears twice in the array, |republican|
% appears twice in the array, and |independent| is unused.  

%% 
% Remove the unused category, |independent|. 
B = removecats(A) 

%%
% |B| has the same values as |A|.  

%% 
% Display the categories of |B|. 
categories(B) 

%%
% |B| has fewer categories than |A|.