# union

Returns the elements that are in matrices `x` and
`y`. If 'rows' is provided then each row will be considered
its on set.

## Syntax

union(x, y)

union(x, y, 'rows')

[c,ia,ib] = union(...)

## Inputs

`x,y`- The sets to find a union of.
`'rows'`- Specifies to search for common rows as opposed to common elements.

## Outputs

- c
- The elements of the union of
`x`and`y`. - ia,ib
- a(ia) and b(ib) are disjoint sets that compose c.

## Examples

Single return
union:

`union([1,5,2;6,2,6],[9;0;1;2])`

```
ans = [Matrix] 6 x 1
0
1
2
5
6
9
```

Multi-return
union:

`[c,ia,ib] = union([1,5,2;6,2,6],[9;0;1;2])`

```
c = [Matrix] 6 x 1
0
1
2
5
6
9
ia = [Matrix] 2 x 1
3
6
ib = [Matrix] 4 x 1
2
3
4
1
```

Multi-return union with rows
option:

`[c,ia,ib]=union([1,5,2;6,2,6],[9,0,1;6,2,6],'rows')`

```
c = [Matrix] 3 x 3
1 5 2
6 2 6
9 0 1
ia = 1
ib = [Matrix] 2 x 1
2
1
```