www.gusucode.com > stats 源码程序 matlab案例代码 > stats/MergeCategoryLevelsExample.m

    %% Merge Category Levels  
% This example shows how to merge categories in a categorical array using
% |mergelevels|. This is useful for collapsing categories with few observations.   

% Copyright 2015 The MathWorks, Inc.


%% Load sample data. 
load carsmall  

%% Create a nominal array. 
% The variable |Origin| is a character array containing the country of origin
% for 100 sample cars. Convert |Origin| to a nominal array. 
Origin = nominal(Origin);
getlevels(Origin) 

%%
% There are six unique countries of origin in the data.  

%% Tabulate category counts. 
% Explore the elements of the categorical array. 
tabulate(Origin) 

%%
% There are relatively few observations in each European country.  

%% Merge categories. 
% Merge the categories |France|, |Germany|, |Italy|, and |Sweden| into one
% category called |Europe|. 
Origin = mergelevels(Origin,{'France','Germany','Italy','Sweden'},...
                     'Europe');
getlevels(Origin) 

%%
% The variable |Origin| now has only three category levels.  

%% Tabulate category counts. 
% Explore the elements of the merged categories. 
tabulate(Origin) 

%%
% The category |Europe| has the 16% of observations that were previously
% distributed across four countries.