Set

In computer science, Set is an interesting abstract data type that stores unique values. It is a collection that allows only one element of each value.

If you have a list of values and you want to make it a unique collection of values, you just have to convert it to a Set. Isn’t it wonderful?

We can also perform some Venn-diagram operations like checking for subset, union, intersect and difference, using either

dot notation – eg. set.union(other) infix notation – set intersect other You can also use distinct(), which returns a List. You can also apply toSet() on a String to convert it into a set of unique characters.

val setA = setOf(1, 2, 3)
setA.union(setOf(3, 4, 5)) // setOf(1, 2, 3, 4, 5)
setA intersect setOf(3, 4, 5) // setOf(3)

val list = listOf(1, 2, 1, 2, 3)
list.toSet() // (1, 2, 3)
list.distinct() // listOf(1, 2, 3)
"Hello".toSet() // setOf('H','e','l','o')