union
Returns a set containing all distinct elements from both collections.
infix fun <T> Array<out T>.union(other: Iterable<T>): Set<T>(source)
fun main() {
val numbers = arrayOf(1, 2, 3)
val moreNumbers = listOf(3, 4, 5)
val unionSet: Set<Int> = numbers union moreNumbers
println(unionSet) // Output: [1, 2, 3, 4, 5]
}