Kotlin Map any()
Syntax & Examples

Syntax of Map.any()

There are 2 variations for the syntax of Map.any() extension function. They are:

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

This extension function returns true if map has at least one entry.

fun <K, V> Map<out K, V>.any( predicate: (Entry<K, V>) -> Boolean ): Boolean

This extension function returns true if at least one entry matches the given predicate.

✐ Examples

1 Check if any entry exists in the map

In this example,

We create a map named map1 with three key-value pairs.
We then use the any() function to check if map1 has at least one entry, which it does.
The result, which is 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)
    val result = map1.any()
    println(result)
}

Output

true

2 Check if any entry matches a predicate in the map

In this example,

We create a map named map2 with three key-value pairs.
We then use the any() function with a predicate that checks if any entry's value is equal to 2 in map2.
As one entry ('b' -> 2) matches the predicate, the result is true, which is printed to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map2 = mapOf('a' to 1, 'b' to 2, 'c' to 3)
    val result = map2.any { entry -> entry.value == 2 }
    println(result)
}

Output

true

3 Check if any entry with a specific key exists in the map

In this example,

We create a map named map3 with three key-value pairs.
We then use the any() function with a predicate that checks if any entry's key is equal to 'd' in map3.
As no entry has a key 'd', the result is false, which is printed to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map3 = mapOf('a' to 1, 'b' to 2, 'c' to 3)
    val result = map3.any { entry -> entry.key == 'd' }
    println(result)
}

Output

false

Summary

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