Kotlin Map isEmpty()
Syntax & Examples

Syntax of Map.isEmpty()

The syntax of Map.isEmpty() function is:

abstract fun isEmpty(): Boolean

This isEmpty() function of Map returns true if the map is empty (contains no elements), false otherwise.

✐ Examples

1 Check if an empty map is empty

In this example,

We create an empty map named map1 with keys of type Int and values of type String.
We then use the isEmpty() function to check if map1 is empty, which it is.
The result, which is true, is printed to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map1 = emptyMap<Int, String>()
    val result = map1.isEmpty()
    println(result)
}

Output

true

2 Check if a non-empty map is empty

In this example,

We create a map named map2 with keys of type Char and values of type Int, containing three key-value pairs.
We then use the isEmpty() function to check if map2 is empty, which it is not.
The result, which is false, 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.isEmpty()
    println(result)
}

Output

false

3 Check if another empty map is empty

In this example,

We create another empty map named map3 with keys of type String and values of type Int.
We then use the isEmpty() function to check if map3 is empty, which it is.
The result, which is true, is printed to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map3 = emptyMap<String, Int>()
    val result = map3.isEmpty()
    println(result)
}

Output

true

Summary

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