Kotlin Tutorials

Kotlin Map minOf()
Syntax & Examples

Syntax of Map.minOf()

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

fun <K, V> Map<out K, V>.minOf( selector: (Entry<K, V>) -> Double ): Double

This minOf() extension function of Map returns the smallest value 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 minOf() function on map1 with a selector based on values converted to Double.
  • 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.minOf { it.value.toDouble() }
    println(result)
}

Output

1.0

2 Get smallest key length as Double in the map

In this example,

  • We create a map named map2 with key-value pairs.
  • We use the minOf() function on map2 with a selector based on key lengths converted to Double.
  • The resulting value is the smallest key length as Double 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.minOf { it.key.length.toDouble() }
    println(result)
}

Output

5.0

3 Get smallest key length as Double in the map

In this example,

  • We create a map named map3 with key-value pairs.
  • We use the minOf() function on map3 with a selector based on key lengths converted to Double.
  • The resulting value is the smallest key length as Double in map3.
  • We print the resulting value to standard output.

Kotlin Program

fun main(args: Array<String>) {
    val map3 = mapOf("one" to 1, "two" to 2, "three" to 3)
    val result = map3.minOf { it.key.length.toDouble() }
    println(result)
}

Output

3.0

Summary

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