Kotlin List isNullOrEmpty()
Syntax & Examples

Syntax of List.isNullOrEmpty()

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

fun <T> Collection<T>?.isNullOrEmpty(): Boolean

This isNullOrEmpty() extension function of List returns true if this nullable collection is either null or empty.

✐ Examples

1 Example

In this example,

We create a nullable list named list1 containing the characters 'a', 'p', 'p', 'l', 'e'.
We use the isNullOrEmpty function to check if list1 is either null or empty.
Since list1 is not null and contains elements, the expression list1.isNullOrEmpty() returns false.
Finally, we print the value of result to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val list1: List<String>? = listOf("a", "p", "p", "l", "e");
    val result = list1.isNullOrEmpty();
    println(result);
}

Output

false

2 Example

In this example,

We create a nullable list named list1 containing the integers 10, 20, 30.
We use the isNullOrEmpty function to check if list1 is either null or empty.
Since list1 is not null and contains elements, the expression list1.isNullOrEmpty() returns false.
Finally, we print the value of result to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val list1: List<Int>? = listOf(10, 20, 30);
    val result = list1.isNullOrEmpty();
    println(result);
}

Output

false

3 Example

In this example,

We create a nullable list named list1 and assign it a null value.
We use the isNullOrEmpty function to check if list1 is either null or empty.
Since list1 is null, the expression list1.isNullOrEmpty() returns true.
Finally, we print the value of result to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val list1: List<String>? = null;
    val result = list1.isNullOrEmpty();
    println(result);
}

Output

true

Summary

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