Java HashSet remove() Method with Examples

by Online Tutorials Library July 22, 2022

Java HashSet remove() Method

The remove() is a method of Java HashSet class which removes the specified element from this set if it is present.

Syntax

Following is the declaration of remove() method:

Parameter

Parameter	Description	Required/Optional
o	It is the object which will be removed to this set, if present.	Required

Returns

The remove() method returns true if the set contained the specified element.

Exceptions

Compatibility Version

Java 1.2 and above

Example 1

  import java.util.*;  public class HashSetRemoveExample1 {  public static void main(String[] args) {  HashSet set=new HashSet();    set.add(“Ravi”);    set.add(“Vijay”);    set.add(“Aman”);    set.add(“Ajay”);    //Display HashSet              System.out.println(“HashSet: ” + set);               //Remove elements using remove() method              set.remove(“Vijay”);              // Displaying the HashSet after removal              System.out.println(“HashSet after removing elements: ” + set);  }  }  

Test it Now

Output:

HashSet: [Vijay, Ravi, Aman, Ajay]  HashSet after removing elements: [Ravi, Aman, Ajay]

Example 2

  import java.util.*;  public class HashSetRemoveExample2 {  public static void main(String[] args) {  HashSet hashSetObject = new HashSet <>();  hashSetObject.add(45);  hashSetObject.add(67);  hashSetObject.add(98);  hashSetObject.add(24);  //Display HashSet              System.out.println(“HashSet: ” + hashSetObject);               //Remove elements using remove() method              hashSetObject.remove(98);              hashSetObject.remove(24);              //Displaying the HashSet after removal            System.out.println(“HashSet after removing elements: ” + hashSetObject);  }  }  

Test it Now

Output:

HashSet: [98, 67, 24, 45]  HashSet after removing elements: [67, 45]

Example 3

  import java.util.*;    class Book {    int id;    String name,author,publisher;    int quantity;    public Book(int id, String name, String author, String publisher, int quantity) {    this.id = id;    this.name = name;    this.author = author;    this.publisher = publisher;    this.quantity = quantity;    }    }    public class HashSetRemoveExample3 {    public static void main(String[] args) {    HashSet set=new HashSet();    //Creating Books    Book b1=new Book(101,”Let us C”,”Yashwant Kanetkar”,”BPB”,8);    Book b2=new Book(102,”Data Communications & Networking”,”Forouzan”,”Mc Graw Hill”,4);    Book b3=new Book(103,”Operating System”,”Galvin”,”Wiley”,6);    //Adding Books to HashSet    set.add(b1);    set.add(b2);    set.add(b3);    //Traversing HashSet    for(Book b:set){    System.out.println(b.id+” “+b.name+” “+b.author+” “+b.publisher+” “+b.quantity);    }   //Removing elements to HashSet  set.remove(b2);   System.out.println(“Books after remove method:”);  for(Book b:set){    System.out.println(b.id+” “+b.name+” “+b.author+” “+b.publisher+” “+b.quantity);    }   }    }    

Test it Now

Output:

103 Operating System Galvin Wiley 6  101 Let us C Yashwant Kanetkar BPB 8  102 Data Communications & Networking Forouzan Mc Graw Hill 4  Books after remove method:  103 Operating System Galvin Wiley 6  101 Let us C Yashwant Kanetkar BPB 8

Next TopicHashSet size() Method

add(E e)clear()clone()contains(Object o)hashset isempty()iterator java remove(Object o)size()spliterator()

Java HashSet remove() Method with Examples

Java HashSet remove() Method

Syntax

Parameter

Returns

Exceptions

Compatibility Version

Example 1

Example 2

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