Start of main content## More like this

Returns every element that exists in any of the two lists once.

- Create a
`set`

with all values of`a`

and`b`

and convert to a`list`

.

```
def union(a, b):
return list(set(a + b))
```

`union([1, 2, 3], [4, 3, 2]) # [1, 2, 3, 4]`

### List union based on function

Python, List

Returns every element that exists in any of the two lists once, after applying the provided function to each element of both.

### Merge lists

Python, List

Merges two or more lists into a list of lists, combining elements from each of the input lists based on their positions.

### List difference based on function

Python, List

Returns the difference between two lists, after applying the provided function to each list element of both.