MATLAB Function Reference
unique

Unique elements of a vector

Syntax

• ```b = unique(A)
b = unique(A,'rows')
[b,m,n] = unique(...)
```

Description

```b = unique(A) ``` returns the same values as in `A` but with no repetitions. The resulting vector is sorted in ascending order. `A` can be a cell array of strings.

```b = unique(A,'rows') ``` returns the unique rows of `A`.

```[b,m,n] = unique(...) ``` also returns index vectors `m` and `n` such that `b = A(m)` and `A = b(n)`. Each element of `m` is the greatest subscript such that `b = A(m)`. For row combinations, `b = A(m,:)` and `A = b(n,:)`.

Examples

• ```A = [1 1 5 6 2 3 3 9 8 6 2 4]
A =
1     1     5     6     2     3     3     9     8     6     2     4

[b,m,n] = unique(A)
b =
1     2     3     4     5     6     8     9
m =
2    11     7    12     3    10     9     8
n =
1     1     5     6     2     3     3     8     7     6     2     4

A(m)
ans =
1     2     3     4     5     6     8     9

b(n)
ans =
1     1     5     6     2     3     3     9     8     6     2     4
```

Because `NaN`s are not equal to each other, `unique` treats them as unique elements.

• ```unique([1 1 NaN NaN])
ans =
1 NaN NaN
```

`intersect`, `ismember`, `issorted`, `setdiff`, `setxor`, `union`