Kotlin Tutorials

Kotlin Set size
Syntax & Examples

Set.size property

The size property of the Set class in Kotlin returns the number of elements in the set.

Syntax of Set.size

The syntax of Set.size property is:

abstract val size: Int

This size property of Set returns the number of elements in the set.

Return Type

Set.size returns value of type Int.


✐ Examples

1 Getting the size of a set

In Kotlin, we can use the size property to get the number of elements in a set.

For example,

  1. Create a set of integers.
  2. Use the size property to get the number of elements in the set.
  3. Print the size to the console using the println function.

Kotlin Program

fun main(args: Array<String>) {
    val numbers = setOf(1, 2, 3, 4, 5)
    val size = numbers.size
    println("The size of the set is: $size")
}

Output

The size of the set is: 5

2 Checking if a set is empty using size

In Kotlin, we can check if a set is empty by comparing the size property to zero.

For example,

  1. Create an empty set of strings.
  2. Check if the size of the set is zero to determine if it is empty.
  3. Print the result to the console using the println function.

Kotlin Program

fun main(args: Array<String>) {
    val emptySet = emptySet<String>()
    val isEmpty = emptySet.size == 0
    println("Is the set empty? $isEmpty")
}

Output

Is the set empty? true

3 Using size property with mutable set

In Kotlin, the size property can also be used with mutable sets to get the number of elements.

For example,

  1. Create a mutable set of strings.
  2. Add elements to the set.
  3. Use the size property to get the number of elements in the set.
  4. Print the size to the console using the println function.

Kotlin Program

fun main(args: Array<String>) {
    val mutableSet = mutableSetOf("apple", "banana", "cherry")
    mutableSet.add("date")
    val size = mutableSet.size
    println("The size of the mutable set is: $size")
}

Output

The size of the mutable set is: 4

Summary

In this Kotlin tutorial, we learned about size property of Set: the syntax and few working examples with output and detailed explanation for each example.