Kotlin Tutorials

Kotlin Map toList()
Syntax & Examples

Syntax of Map.toList()

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

fun <K, V> Map<out K, V>.toList(): List<Pair<K, V>>

This toList() extension function of Map returns a List containing all key-value pairs.


✐ Examples

1 Convert map entries to list

In this example,

  • We create a map named map1 containing key-value pairs 1 to 'a', 2 to 'b', and 3 to 'c'.
  • We then apply the toList() function on map1 to convert the map entries into a list of pairs.
  • The resulting list contains pairs representing the entries of the map.
  • We print the result to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map1 = mapOf(1 to 'a', 2 to 'b', 3 to 'c');
    val result = map1.toList()
    print(result);
}

Output

[(1, a), (2, b), (3, c)]

2 Convert map entries to list

In this example,

  • We create a map named map2 containing key-value pairs 'a' to 1, 'b' to 2, and 'c' to 3.
  • We then apply the toList() function on map2 to convert the map entries into a list of pairs.
  • The resulting list contains pairs representing the entries of the map.
  • We print the result to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map2 = mapOf('a' to 1, 'b' to 2, 'c' to 3);
    val result = map2.toList()
    print(result);
}

Output

[(a, 1), (b, 2), (c, 3)]

3 Convert map entries to list

In this example,

  • We create a map named map3 containing key-value pairs 1 to "apple", 2 to "banana", and 3 to "cherry".
  • We then apply the toList() function on map3 to convert the map entries into a list of pairs.
  • The resulting list contains pairs representing the entries of the map.
  • We print the result to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map3 = mapOf(1 to "apple", 2 to "banana", 3 to "cherry");
    val result = map3.toList()
    print(result);
}

Output

[(1, apple), (2, banana), (3, cherry)]

Summary

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