# categories

Categories of categorical array

## Syntax

``C = categories(A)``

## Description

example

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

## Examples

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Create a categorical array, `A`.

`A = categorical({'plane' 'car' 'train' 'car' 'plane'})`
```A = 1x5 categorical plane car train car plane ```

`A` is a 1-by-5 categorical array.

Display the categories of `A`.

`C = categories(A)`
```C = 3x1 cell {'car' } {'plane'} {'train'} ```

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 = 3x2 categorical medium large small xlarge large medium ```

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

Display the categories of `A`.

`C = categories(A)`
```C = 4x1 cell {'small' } {'medium'} {'large' } {'xlarge'} ```

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

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

## Tips

• `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`.

## Version History

Introduced in R2013b