Kotlin Tutorials

Kotlin Set maxOf()
Syntax & Examples

Set.maxOf() extension function

The maxOf() extension function in Kotlin returns the largest value among all values produced by the selector function applied to each element in the collection.

Syntax of Set.maxOf()

The syntax of Set.maxOf() extension function is:

fun <T> Set<T>.maxOf(selector: (T) -> Double): Double

This maxOf() extension function of Set returns the largest value among all values produced by selector function applied to each element in the collection.

Parameters

ParameterOptional/RequiredDescription
selectorrequiredA function that takes an element and returns a Double value to be compared.

Return Type

Set.maxOf() returns value of type Double.


✐ Examples

1 Finding the maximum value among integers transformed to double

Using maxOf() to find the maximum value among integers in a set transformed to double.

For example,

  1. Create a set of integers.
  2. Use maxOf() with a selector function that transforms each integer to double.
  3. Print the resulting maximum value.

Kotlin Program

fun main() {
    val numbers = setOf(1, 2, 3, 4, 5)
    val maxValue = numbers.maxOf { it.toDouble() }
    println(maxValue)
}

Output

5.0

2 Finding the maximum length of strings

Using maxOf() to find the maximum length among strings in a set.

For example,

  1. Create a set of strings.
  2. Use maxOf() with a selector function that returns the length of each string as a double.
  3. Print the resulting maximum length.

Kotlin Program

fun main() {
    val strings = setOf("one", "two", "three")
    val maxLength = strings.maxOf { it.length.toDouble() }
    println(maxLength)
}

Output

5.0

3 Finding the maximum age among custom objects

Using maxOf() to find the maximum age among custom objects in a set.

For example,

  1. Create a data class.
  2. Create a set of custom objects.
  3. Use maxOf() with a selector function that returns the age of each object as a double.
  4. Print the resulting maximum age.

Kotlin Program

data class Person(val name: String, val age: Int)

fun main() {
    val people = setOf(Person("Alice", 30), Person("Bob", 25), Person("Charlie", 35))
    val maxAge = people.maxOf { it.age.toDouble() }
    println(maxAge)
}

Output

35.0

Summary

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