Kotlin List randomOrNull()
Syntax & Examples

Syntax of List.randomOrNull()

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

1.
fun <T> Collection<T>.randomOrNull(): T?

This extension function returns a random element from this collection, or null if this collection is empty.

2.
fun <T> Collection<T>.randomOrNull(random: Random): T?

This extension function returns a random element from this collection using the specified source of randomness, or null if this collection is empty.


✐ Examples

1 Example

In this example,

  • We create a list named list containing the integers [1, 2, 3, 4, 5].
  • We use the randomOrNull() function to get a random element from the list.
  • Finally, we print the random element to standard output using the println function.

Kotlin Program

fun main(args: Array<String>) {
    val list = listOf(1, 2, 3, 4, 5);
    val randomElement = list.randomOrNull();
    println(randomElement);
}

Output

4

2 Example

In this example,

  • We create a list named list containing the characters ['a', 'b', 'c', 'd', 'e'].
  • We use the randomOrNull() function to get a random element from the list.
  • Finally, we print the random element to standard output using the println function.

Kotlin Program

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

Output

c

3 Example

In this example,

  • We create a list named list containing the strings ['apple', 'banana', 'cherry', 'date', 'elderberry'].
  • We use the randomOrNull() function to get a random element from the list.
  • Finally, we print the random element to standard output using the println function.

Kotlin Program

fun main(args: Array<String>) {
    val list = listOf("apple", "banana", "cherry", "date", "elderberry");
    val randomElement = list.randomOrNull();
    println(randomElement);
}

Output

banana

Summary

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