Check if a List is empty in Kotlin

This article explores different ways to check if a List is empty in Kotlin.

1. Using `isEmpty()` function

The standard solution to check if a list is empty in Kotlin is with the isEmpty() library function. It returns true if the list contains no elements, false otherwise. Following is a simple example demonstrating the usage of this method, which handles null input gracefully.

fun isEmpty(list: List<*>?): Boolean {

return list == null || list.isEmpty()

}

fun main() {

val list = listOf<Int>()

val isEmpty = isEmpty(list)

if (isEmpty) {

println("The list is empty")

} else {

println("The list is not empty")

}

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Output:

The list is empty

2. Using `isNotEmpty()` function

Alternatively, we can check if the list is not empty using the isNotEmpty() function. This is demonstrated below:

fun isNotEmpty(list: List<*>?): Boolean {

return list != null && list.isNotEmpty()

}

fun main() {

val list = listOf<Int>()

val isNotEmpty = isNotEmpty(list)

if (isNotEmpty) {

println("The list is not empty")

} else {

println("The list is empty")

}

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Output:

The list is empty

3. Checking List of Lists

To check for an empty list or a null value in a List of Lists, we can use the any() function that returns true if at least one element matches the given predicate.

fun isAnyEmpty(listOfLists: List<List<Int>?>): Boolean {

return listOfLists.any { it == null || it.isEmpty() }

}

fun main() {

val listOfLists = listOf(listOf(1, 2, 3), null, listOf(4, 5))

val isAnyEmpty = isAnyEmpty(listOfLists)

if (isAnyEmpty) {

println("The list contains a null or an empty list")

}

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Output:

The list contains a null or an empty list

That’s all about checking if a List is empty in Kotlin.

Check if a List is empty in Kotlin

1. Using isEmpty() function

2. Using isNotEmpty() function

3. Checking List of Lists

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1. Using `isEmpty()` function

2. Using `isNotEmpty()` function