The contains
method in Kotlin checks whether a HashSet contains a specific value.
fun contains(element: E): Boolean
element
: This represents the value whose presence we want to check inside the HashSet.This method returns true
if the passed value is present inside the HashSet. It returns false
if the value is not present inside the HashSet.
The code snippet below demonstrates how to check for the existence of a value inside a HashSet using the contains
method.
fun main() {//Creating a new HashSet that can have integer types as elementsvar set: HashSet<Int> = hashSetOf<Int>()// Adding four entriesset.add(1)set.add(2)set.add(3)set.add(4)println("\nThe set is : $set")// Checking if the set contains the element 1println("\nset.contains(1) :" + set.contains(1));// Checking if the set contains the element 5println("\nset.contains(5) :" + set.contains(5));}
Line 3: We create a new HashSet object named set
. We use the hashSetOf()
method to create an empty HashSet.
Lines 6–9: We add four new elements 1
, 2
, 3
, and 4
to set
using the add()
method.
Line 14: We use the contains
method to check if set
contains the element 1
. The element 1
is present in set
, so the method returns true
.
Line 17: We use the contains
method to check if set
contains the element 5
. The element 5
is not present in set
, so the method returns false
.