Kotlin List toCollection()
Syntax & Examples

Syntax of List.toCollection()

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

fun <T, C : MutableCollection<in T>> Iterable<T>.toCollection( destination: C ): C

This toCollection() extension function of List appends all elements to the given destination collection.


✐ Examples

1 Example

In this example,

  • We create a list of integers named list1 with elements 1, 2, 3, 4, 5.
  • We create an empty mutable list named list2.
  • We use the toCollection() function on list1 to append its elements to list2.
  • We then print the elements of list2 using joinToString() to display them separated by commas.

Kotlin Program

fun main(args: Array<String>) {
    val list1 = listOf(1, 2, 3, 4, 5)
    val list2 = mutableListOf<Int>()
    list1.toCollection(list2)
    println(list2.joinToString())
}

Output

1, 2, 3, 4, 5

2 Example

In this example,

  • We create a list of characters named list1 with elements 'a', 'b', 'c'.
  • We create an empty mutable list named list2.
  • We use the toCollection() function on list1 to append its elements to list2.
  • We then print the elements of list2 using joinToString() to display them separated by commas.

Kotlin Program

fun main(args: Array<String>) {
    val list1 = listOf('a', 'b', 'c')
    val list2 = mutableListOf<Char>()
    list1.toCollection(list2)
    println(list2.joinToString())
}

Output

a, b, c

3 Example

In this example,

  • We create a list of strings named list1 with elements "apple", "banana", "cherry".
  • We create an empty mutable list named list2.
  • We use the toCollection() function on list1 to append its elements to list2.
  • We then print the elements of list2 using joinToString() to display them separated by commas.

Kotlin Program

fun main(args: Array<String>) {
    val list1 = listOf("apple", "banana", "cherry")
    val list2 = mutableListOf<String>()
    list1.toCollection(list2)
    println(list2.joinToString())
}

Output

apple, banana, cherry

Summary

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