toMutableSet

Returns a new MutableSet containing all distinct elements from the given array.

fun <T> Array<out T>.toMutableSet(): MutableSet<T>(source)

val array = arrayOf("apple", "banana", "apple", "cherry")
val mutableSet = array.toMutableSet()

mutableSet.add("date")          // add a new element
mutableSet.remove("banana")     // remove an element

println(mutableSet)             // prints something like [apple, cherry, date]

Source