kotlin-stdlib / kotlin.collections / setOf

setOf

Common
JVM
JS
Native
1.0
fun <T> setOf(vararg elements: T): Set<T>
(source)

Returns a new read-only set with the given elements. Elements of the set are iterated in the order they were specified. The returned set is serializable (JVM).

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val set1 = setOf(1, 2, 3)
val set2 = setOf(3, 2, 1)

// setOf preserves the iteration order of elements
println(set1) // [1, 2, 3]
println(set2) // [3, 2, 1]

// but the sets with the same elements are equal no matter of order
println("set1 == set2 is ${set1 == set2}") // true
//sampleEnd
}
Common
JVM
JS
Native
1.0
For Common

Returns a new read-only set containing only the specified object element.

The returned set is serializable (JVM).

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val set = setOf('a')
println(set) // [a]
println(set.size) // 1
//sampleEnd
}
For JVM

Returns a new read-only set containing only the specified object element.

The returned set is serializable.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val set = setOf('a')
println(set) // [a]
println(set.size) // 1
//sampleEnd
}
For JS, Native

Returns a new read-only set containing only the specified object element.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val set = setOf('a')
println(set) // [a]
println(set.size) // 1
//sampleEnd
}
Common
JVM
JS
Native
1.0
fun <T> setOf(): Set<T>
(source)

Returns an empty read-only set. The returned set is serializable (JVM).

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val set = setOf<String>()
println("set.isEmpty() is ${set.isEmpty()}") // true

// another way to create an empty set,
// type parameter is inferred from the expected type
val other: Set<Int> = emptySet()

// Empty sets are equal

println("set == other is ${set == other}") // true
println(set) // []
//sampleEnd
}