Kotlin Map isNotEmpty()
Syntax & Examples

Syntax of Map.isNotEmpty()

The syntax of Map.isNotEmpty() extension function is:

fun <K, V> Map<out K, V>.isNotEmpty(): Boolean

This isNotEmpty() extension function of Map returns true if this map is not empty.

✐ Examples

1 Non-empty map

In this example,

We create a map named map1 containing key-value pairs.
We use the isNotEmpty() function to check if map1 is not empty.
As map1 contains elements, true is printed to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map1 = mapOf("a" to 1, "b" to 2, "c" to 3)
    println(map1.isNotEmpty())
}

Output

true

2 Empty map

In this example,

We create an empty map named map2.
We use the isNotEmpty() function to check if map2 is not empty.
As map2 does not contain any elements, false is printed to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map2 = mapOf<Int, Char>()
    println(map2.isNotEmpty())
}

Output

false

3 Non-empty map

In this example,

We create a map named map3 containing key-value pairs.
We use the isNotEmpty() function to check if map3 is not empty.
As map3 contains elements, true is printed to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map3 = mapOf(1 to "apple", 2 to "banana", 3 to "cherry")
    println(map3.isNotEmpty())
}

Output

true

Summary

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