Kotlin List toMutableSet()
Syntax & Examples

Syntax of List.toMutableSet()

The syntax of List.toMutableSet() extension function is:

fun <T> Iterable<T>.toMutableSet(): MutableSet<T>

This toMutableSet() extension function of List returns a new MutableSet containing all distinct elements from the given collection.

✐ Examples

1 Example

In this example,

We create a list named list1 containing integers 1, 2, 2, 3, 4, 4, 5.
We convert list1 to a MutableSet using the toMutableSet() extension function.
We print the mutableSet to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val list1 = listOf(1, 2, 2, 3, 4, 4, 5)
    val mutableSet = list1.toMutableSet()
    println(mutableSet)
}

Output

[1, 2, 3, 4, 5]

2 Example

In this example,

We create a list named list2 containing characters 'a', 'b', 'c', 'c', 'd'.
We convert list2 to a MutableSet using the toMutableSet() extension function.
We print the mutableSet to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val list2 = listOf('a', 'b', 'c', 'c', 'd')
    val mutableSet = list2.toMutableSet()
    println(mutableSet)
}

Output

[a, b, c, d]

3 Example

In this example,

We create a list named list3 containing strings "apple", "banana", "apple", "cherry".
We convert list3 to a MutableSet using the toMutableSet() extension function.
We print the mutableSet to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val list3 = listOf("apple", "banana", "apple", "cherry")
    val mutableSet = list3.toMutableSet()
    println(mutableSet)
}

Output

[apple, banana, cherry]

Summary

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