Kotlin List elementAtOrElse()
Syntax & Examples

Syntax of List.elementAtOrElse()

There are 2 variations for the syntax of List.elementAtOrElse() extension function. They are:

fun <T> List<T>.elementAtOrElse( index: Int, defaultValue: (Int) -> T ): T

This extension function returns an element at the given index or the result of calling the defaultValue function if the index is out of bounds of this list.

fun <T> Iterable<T>.elementAtOrElse( index: Int, defaultValue: (Int) -> T ): T

This extension function returns an element at the given index or the result of calling the defaultValue function if the index is out of bounds of this collection.

✐ Examples

1 Example

In this example,

We create a list named list1 containing the integers 10, 20, 30.
Then we use the elementAtOrElse function on list1 to access the element at index 1.
Since index 1 exists in list1, the element at that index, which is 20, is returned.
We specify a default value 100 as the second argument of elementAtOrElse, but it's not used because the index 1 is valid.
Finally, we print the value of result to standard output using the print statement.

Kotlin Program

fun main(args: Array<String>) {
    val list1 = listOf(10, 20, 30);
    val result = list1.elementAtOrElse(1) { 100 }
    print(result);
}

Output

2 Example

In this example,

We create a list named list2 containing the characters 'a', 'b', 'c'.
Then we use the elementAtOrElse function on list2 to access the element at index 5.
Since index 5 is out of bounds for list2, the default value function { 'z' } is called, and it returns 'z'.
Finally, we print the value of result to standard output using the print statement.

Kotlin Program

fun main(args: Array<String>) {
    val list2 = listOf('a', 'b', 'c');
    val result = list2.elementAtOrElse(5) { 'z' }
    print(result);
}

Output

3 Example

In this example,

We create a list named list3 containing the strings "apple", "banana", "cherry".
Then we use the elementAtOrElse function on list3 to access the element at index 10.
Since index 10 is out of bounds for list3, the default value function { "not found" } is called, and it returns "not found".
Finally, we print the value of result to standard output using the print statement.

Kotlin Program

fun main(args: Array<String>) {
    val list3 = listOf("apple", "banana", "cherry");
    val result = list3.elementAtOrElse(10) { "not found" }
    print(result);
}

Output

not found

Summary

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