Kotlin Map getOrDefault()
Syntax & Examples

Syntax of Map.getOrDefault()

The syntax of Map.getOrDefault() function is:

open fun getOrDefault(key: K, defaultValue: V): V

This getOrDefault() function of Map returns the value corresponding to the given key, or defaultValue if such a key is not present in the map.

✐ Examples

1 Get value for an existing key in the map

In this example,

We create a map named map with integer keys and character values.
We use the getOrDefault() function to retrieve the value for key 2. Since key 2 exists in the map, its corresponding value 'b' is returned.
The result, which is 'b', is printed to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map = mapOf(1 to 'a', 2 to 'b', 3 to 'c')
    val result = map.getOrDefault(2, 'z')
    println(result)
}

Output

2 Get value for an existing key in the map with a default value

In this example,

We create a map named map with string keys and integer values.
We use the getOrDefault() function to retrieve the value for key 'banana'. Since key 'banana' exists in the map, its corresponding value 2 is returned.
The result, which is 2, is printed to standard output.

Kotlin Program

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

Output

3 Get default value for a non-existing key in the map

In this example,

We create a map named map with integer keys and character values.
We use the getOrDefault() function to retrieve the value for key 4. Since key 4 does not exist in the map, the default value 'z' is returned.
The result, which is 'z', is printed to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map = mapOf(1 to 'a', 2 to 'b', 3 to 'c')
    val result = map.getOrDefault(4, 'z')
    println(result)
}

Output

Summary

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