Kotlin Tutorials

Kotlin Map minOfWith()
Syntax & Examples

Syntax of Map.minOfWith()

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

fun <K, V, R> Map<out K, V>.minOfWith( comparator: Comparator<in R>, selector: (Entry<K, V>) -> R ): R

This minOfWith() extension function of Map returns the smallest value according to the provided comparator among all values produced by selector function applied to each entry in the map.


✐ Examples

1 Get smallest value in the map

In this example,

  • We create a map named map1 with key-value pairs.
  • We use the minOfWith() function on map1 with a custom comparator comparing values.
  • The resulting value is the smallest among all values in map1.
  • We print the resulting value to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map1 = mapOf("key1" to 1, "key2" to 2, "key3" to 3)
    val result = map1.minOfWith(Comparator { o1, o2 -> o1.compareTo(o2) }, { it.value })
    println(result)
}

Output

1

2 Get smallest key length in the map

In this example,

  • We create a map named map2 with key-value pairs.
  • We use the minOfWith() function on map2 with a custom comparator comparing key lengths.
  • The resulting value is the smallest key length in map2.
  • We print the resulting value to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map2 = mapOf("apple" to 1, "banana" to 2, "cherry" to 3)
    val result = map2.minOfWith(Comparator { o1, o2 -> o1.compareTo(o2) }, { it.key.length })
    println(result)
}

Output

5

Summary

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