setUnion
setUnion(set1, set2)
Create the union of two (multi)sets. Multi-dimension arrays will be converted to single-dimension arrays before the operation.
Try it yourself:
| $1 | setUnion([1, 2, 3, 4], [3, 4, 5, 6])
| |
| $2 | setUnion([[1, 2], [3, 4]], [[3, 4], [5, 6]])
|