Kotlin List orEmpty()
Syntax & Examples

Syntax of List.orEmpty()

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

fun <T> List<T>?.orEmpty(): List<T>

This orEmpty() extension function of List returns this List if it's not null and the empty list otherwise.

✐ Examples

1 Example

In this example,

We declare a nullable list named list and assign it a value of null.
We apply the orEmpty() function to the list, which returns an empty list because the original list is null.
Finally, we print the resulting empty list to standard output using the println function.

Kotlin Program

fun main(args: Array<String>) {
    val list: List<String>? = null;
    val result = list.orEmpty();
    println(result);
}

Output

[]

2 Example

In this example,

We create a list named list containing the characters ['a', 'b', 'c', 'd', 'e'].
We apply the orEmpty() function to the list, which returns the original list because it's not null.
Finally, we print the original list to standard output using the println function.

Kotlin Program

fun main(args: Array<String>) {
    val list = listOf('a', 'b', 'c', 'd', 'e');
    val result = list.orEmpty();
    println(result);
}

Output

[a, b, c, d, e]

3 Example

In this example,

We create a list named list containing the strings ['apple', 'banana', 'orange', 'grape'].
We apply the orEmpty() function to the list, which returns the original list because it's not null.
Finally, we print the original list to standard output using the println function.

Kotlin Program

fun main(args: Array<String>) {
    val list = listOf("apple", "banana", "orange", "grape");
    val result = list.orEmpty();
    println(result);
}

Output

[apple, banana, orange, grape]

Summary

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