Categorical Arrays

Arrays of qualitative data with values from a finite set of discrete, nonnumeric data

categorical is a data type to store data with values from a finite set of discrete categories. For example, the syntax C = categorical({'R','G','B','B','G','B'}) creates a categorical array with six elements that belong to the categories R, G, or B.

A categorical array provides efficient storage and convenient manipulation of nonnumeric data, while also maintaining meaningful names for the data values. The categories can have a natural order, but it is not required. For more information see Create Categorical Arrays or watch Tables and Categorical Arrays.

Functions

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Create Categorical Arrays

`categorical`	Array that contains values assigned to categories
`discretize`	Group data into bins or categories

Determine Categories and Type

`categories`	List of categories in categorical array
`iscategorical`	Determine if input is categorical array
`iscategory`	Determine if inputs are names of categories
`isordinal`	Determine if input is ordinal categorical array
`isprotected`	Determine if categories of categorical array are protected
`isundefined`	Find undefined elements in categorical array

Add, Delete, or Modify Categories

`addcats`	Add categories to categorical array
`mergecats`	Merge categories in categorical array
`removecats`	Remove categories from categorical array
`renamecats`	Rename categories in categorical array
`reordercats`	Reorder categories in categorical array
`setcats`	Set categories in categorical array
`combinations`	Generate all element combinations of arrays (Since R2023a)

Summary Information

`summary`	Data summary
`countcats`	Count occurrences of categorical array elements by category

Topics

Create Categorical Arrays

Create categorical arrays from various types of input data and modify their elements.
Access Data Using Categorical Arrays

Search, select, and delete elements from categorical arrays.
Advantages of Using Categorical Arrays
Categorical arrays provide a natural representation of data, mathematical ordering of character vectors, and efficient memory usage.
Core Functions Supporting Categorical Arrays
Many functions in MATLAB^® operate on categorical arrays in much the same way that they operate on other arrays. A few of these functions might exhibit special behavior when operating on a categorical array.