Java by API/java.util/HashSet

HashSet: addAll(Collection<?> c)

   <source lang="java">

import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Main {

 public static void main(String[] a) {
   String elements[] = { "A", "B", "C", "D", "E" };
   Set<String> set = new HashSet<String>(Arrays.asList(elements));
   elements = new String[] { "E", "F" };
   set.addAll(Arrays.asList(elements));
   System.out.println(set);
 }

}

 </source>
   
  
 
  

HashSet: add(E o)

   <source lang="java">

/**

*Output: 

[D, A, F, C, B, E]

*/

import java.util.HashSet; public class MainClass {

 public static void main(String args[]) {
   HashSet<String> hs = new HashSet<String>();
   hs.add("B");
   hs.add("A");
   hs.add("D");
   hs.add("E");
   hs.add("C");
   hs.add("F");
   System.out.println(hs);
 }

}

 </source>
   
  
 
  

HashSet: clear()

   <source lang="java">

import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Main {

 public static void main(String[] a) {
   String elements[] = { "A", "B", "C", "D", "E" };
   Set<String> set = new HashSet<String>(Arrays.asList(elements));
   elements = new String[] { "E", "F" };
   set.addAll(Arrays.asList(elements));
   System.out.println(set);
   set.clear();
   System.out.println(set);
 }

}

 </source>
   
  
 
  

HashSet: clone()

   <source lang="java">

import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Main {

 public static void main(String[] a) {
   String elements[] = { "A", "B", "C", "D", "E" };
   Set<String> set = new HashSet<String>(Arrays.asList(elements));
   Set set2 = ((Set) ((HashSet) set).clone());
   System.out.println(set2);
 }

}

 </source>
   
  
 
  

HashSet: containsAll(Collection<?> c)

   <source lang="java">

import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Main {

 public static void main(String[] a) {
   String elements[] = { "A", "B", "C", "D", "E" };
   Set<String> set = new HashSet<String>(Arrays.asList(elements));
   elements = new String[] { "A", "B", "C" };
   Set<String> set2 = new HashSet<String>(Arrays.asList(elements));
   System.out.println(set.containsAll(set2));
 }

}

 </source>
   
  
 
  

HashSet: contains(Object o)

   <source lang="java">

import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Main {

 public static void main(String[] a) {
   String elements[] = { "A", "B", "C", "D", "E" };
   Set<String> set = new HashSet<String>(Arrays.asList(elements));
   System.out.println(set.contains("A"));
 }

}

 </source>
   
  
 
  

HashSet: isEmpty()

   <source lang="java">

import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Main {

 public static void main(String[] a) {
   String elements[] = { "A", "B", "C", "D", "E" };
   Set<String> set = new HashSet<String>(Arrays.asList(elements));
   System.out.println(set.isEmpty());
 }

}

 </source>
   
  
 
  

HashSet: iterator()

   <source lang="java">

import java.util.Arrays; import java.util.HashSet; import java.util.Iterator; import java.util.Set; public class Main {

 public static void main(String[] a) {
   String elements[] = { "A", "B", "C", "D", "E" };
   Set<String> set = new HashSet<String>(Arrays.asList(elements));
   Iterator iter = set.iterator();
   while (iter.hasNext()) {
     System.out.println(iter.next());
   }
 }

}

 </source>
   
  
 
  

HashSet: removeAll(Collection<?> c)

   <source lang="java">

import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Main {

 public static void main(String[] a) {
   String elements[] = { "A", "B", "C", "D", "E" };
   Set<String> set = new HashSet<String>(Arrays.asList(elements));
   elements = new String[] { "B", "D", "F", "G", "1", "2", "3", "4" };
   Set<String> set2 = new HashSet<String>(Arrays.asList(elements));
   set.removeAll(set2);
   System.out.println(set);
 }

}

 </source>
   
  
 
  

HashSet: size()

   <source lang="java">

import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Main {

 public static void main(String[] a) {
   String elements[] = { "A", "B", "C", "D", "E" };
   Set<String> set = new HashSet<String>(Arrays.asList(elements));
   System.out.println(set.size());
 }

}

 </source>
   
  
 
  

HashSet: toArray()

   <source lang="java">

import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Main {

 public static void main(String[] a) {
   String elements[] = { "A", "B", "C", "D", "E" };
   Set<String> set = new HashSet<String>(Arrays.asList(elements));
   Object[] arrObj = set.toArray();
   for (int i = 0; i < arrObj.length; i++) {
     System.out.println(arrObj[i]);
   }
   System.out.println(set); 
 }

}

 </source>
   
  
 
  

new HashSet(Collection<?> c)

   <source lang="java">

import java.util.ArrayList; import java.util.HashSet; import java.util.List; import java.util.Set; public class Main {

 public static void main(String[] args) {
   List<String> myList = new ArrayList<String>();
   myList.add("Hello");
   myList.add("World");
   myList.add("World");
   Set<String> set = new HashSet<String>(myList);
   System.out.println(set);
 }

}

 </source>
   
  
 
  

new HashSet < E > ()

   <source lang="java">

/**

*Output: 

[D, A, F, C, B, E]

*/

import java.util.HashSet; public class MainClass {

 public static void main(String args[]) {
   HashSet<String> hs = new HashSet<String>();
   hs.add("B");
   hs.add("A");
   hs.add("D");
   hs.add("E");
   hs.add("C");
   hs.add("F");
   System.out.println(hs);
 }

}

 </source>