This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English verison of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.


Categories of categorical array




C = categories(A) returns a cell array of character vectors containing the categories of the categorical array, A.


collapse all

Create a categorical array, A.

A = categorical({'plane' 'car' 'train' 'car' 'plane'})
A = 

     plane      car      train      car      plane 

A is a 1-by-5 categorical array.

Display the categories of A.

C = categories(A)
C =

  3×1 cell array


Since you created A by specifying only an input array, the categories appear in alphabetical order.

Create an ordinal categorical array.

A = categorical({'medium' 'large'; 'small' 'xlarge'; 'large' 'medium'},...
    {'small' 'medium' 'large' 'xlarge'},'Ordinal',true)
A = 

     medium      large  
     small       xlarge 
     large       medium 

A is a 3-by-2 ordinal categorical array.

Display the categories of A.

C = categories(A)
C =

  4×1 cell array


The categories appear in the order in which you specified them. Since A is ordinal, the categories have the mathematical ordering small < medium < large < xlarge.

Input Arguments

collapse all

Categorical array, specified as a vector, matrix, or multidimensional array.

More About

collapse all

Tall Array Support

This function fully supports tall arrays. For more information, see Tall Arrays.


  • C includes all categories in A, even if A does not contain any data from a category. To see the unique values in A, use unique(A).

  • The order of the categories listed in C is the same order used by functions, such as summary and histogram. To change the order of the categories, use reordercats.

Introduced in R2013b

Was this topic helpful?