HashSet in java




HashSet used to store the data and Its remove Duplicate data.The data stored in Hashtable.








Add
import java.util.HashSet;

public class Main
{
       public static void main(String[] args) 
       {
             HashSet<Integer> num = new HashSet<Integer>();

             num.add(1);
             num.add(2);
             num.add(3);
             num.add(1);
             
             System.out.print(num);

       }
}


Output



[1, 2, 3]









Contains
import java.util.HashSet;

public class Main
{
       public static void main(String[] args) 
       {
             HashSet<Integer> num = new HashSet<Integer>();

             num.add(1);
             num.add(2);
             num.add(3);
             
             System.out.print(num.contains(1));
       }
}


Output



true









Remove
import java.util.HashSet;

public class Main
{
       public static void main(String[] args) 
       {
             HashSet<Integer> num = new HashSet<Integer>();

             num.add(1);
             num.add(2);
             num.add(3);

             num.remove(1);
             
             System.out.print(num);

       }
}


Output



[2, 3]









Size
import java.util.HashSet;

public class Main
{
       public static void main(String[] args) 
       {
             HashSet<Integer> num = new HashSet<Integer>();

             num.add(1);
             num.add(2);
             num.add(3);
             
             System.out.print(num.size());

       }
}


Output



3








Clear
import java.util.HashSet;

public class Main
{
       public static void main(String[] args) 
       {
             HashSet<Integer> num = new HashSet<Integer>();

             num.add(1);
             num.add(2);
             num.add(3);

             num.clear();
             
             System.out.print(num);

       }
}


Output



[]










print each element:
import java.util.HashSet;

public class Main
{
       public static void main(String[] args) 
       {
             HashSet<Integer> num = new HashSet<Integer>();

             num.add(1);
             num.add(2);
             num.add(3);

             for(int i : num)
             {
                   System.out.println(i);
             }

       }
}


Output



1
2
3







String:



Add
import java.util.HashSet;

public class Main
{
       public static void main(String[] args) 
       {
             HashSet<String> names = new HashSet<String>();

             names.add("jack");
             names.add("stark");
             names.add("steve");

             System.out.println(names);
       }
}


Output



[stark, steve, jack]