Kotlin Tutorials

Kotlin Set toList()
Syntax & Examples

Set.toList() extension function

The toList() extension function in Kotlin returns a List containing all elements of the collection.

Syntax of Set.toList()

The syntax of Set.toList() extension function is:

fun <T> Set<T>.toList(): List<T>

This toList() extension function of Set returns a List containing all elements.

Return Type

Set.toList() returns value of type List.


✐ Examples

1 Converting a set of integers to a list

Using toList() to convert a set of integers to a list.

For example,

  1. Create a set of integers.
  2. Use toList() to convert the set to a list.
  3. Print the resulting list.

Kotlin Program

fun main() {
    val intSet = setOf(1, 2, 3)
    val intList = intSet.toList()
    println(intList)
}

Output

[1, 2, 3]

2 Converting a set of strings to a list

Using toList() to convert a set of strings to a list.

For example,

  1. Create a set of strings.
  2. Use toList() to convert the set to a list.
  3. Print the resulting list.

Kotlin Program

fun main() {
    val stringSet = setOf("one", "two", "three")
    val stringList = stringSet.toList()
    println(stringList)
}

Output

[one, two, three]

3 Converting a set of custom objects to a list

Using toList() to convert a set of custom objects to a list.

For example,

  1. Create a data class.
  2. Create a set of custom objects.
  3. Use toList() to convert the set to a list.
  4. Print the resulting list.

Kotlin Program

data class Person(val name: String, val age: Int)

fun main() {
    val peopleSet = setOf(Person("Alice", 30), Person("Bob", 25), Person("Charlie", 35))
    val peopleList = peopleSet.toList()
    println(peopleList)
}

Output

[Person(name=Alice, age=30), Person(name=Bob, age=25), Person(name=Charlie, age=35)]

Summary

In this Kotlin tutorial, we learned about toList() extension function of Set: the syntax and few working examples with output and detailed explanation for each example.