Java by API/java.util/Set

Set: addAll(Collection c)

   <source lang="java">

/*

Output:

true false

* */

import java.util.HashSet; import java.util.Set; public class MainClass {

 public static void main(String args[]) {
   Set set = new HashSet();
   Set set2 = new HashSet();
   StringBuffer buff1 = new StringBuffer("Irish Setter");
   StringBuffer buff2 = new StringBuffer("Irish Setter");
   set.add(buff1);
   set2.add(buff2);
   System.out.println(set.addAll(set2));
   System.out.println(set.addAll(set));
 }

}

 </source>
   
  
 
  

Set: add(String e)

   <source lang="java">

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

 public static void main(String[] a) {
   Set<String> set = new HashSet<String>();
   set.add("Hello");
   if (set.add("Hello")) {
     System.out.println("addition successful");
   } else {
     System.out.println("addition failed");
   }
 }

}

 </source>
   
  
 
  

Set: 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>
   
  
 
  

Set: clone()

   <source lang="java">

/*

Output:

[I, P, G, E] [I, P, G, E]

* */

import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class MainClass {

 public static void main(String args[]) throws Exception {
   String elements[] = { "I", "P", "E", "G", "P" };
   Set set = new HashSet(Arrays.asList(elements));
   Set set2 = ((Set) ((HashSet) set).clone());
   System.out.println(set2);
   FileOutputStream fos = new FileOutputStream("set.ser");
   ObjectOutputStream oos = new ObjectOutputStream(fos);
   oos.writeObject(set);
   oos.close();
   FileInputStream fis = new FileInputStream("set.ser");
   ObjectInputStream ois = new ObjectInputStream(fis);
   Set set3 = (Set) ois.readObject();
   ois.close();
   System.out.println(set3);
 }

}

 </source>
   
  
 
  

Set: 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>
   
  
 
  

Set: 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>
   
  
 
  

Set: equals(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));
   elements = new String[] { "A", "B", "C", "D" };
   Set<String> set2 = new HashSet<String>(Arrays.asList(elements));
   System.out.println(set.equals(set2));
 }

}

 </source>
   
  
 
  

Set: 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>
   
  
 
  

Set: iterator()

   <source lang="java">

/*

Output:

I P G E

* */

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

 public static void main(String args[]) {
   String elements[] = { "I", "P", "E", "G", "P" };
   Set set = new HashSet(Arrays.asList(elements));
   Iterator iter = set.iterator();
   while (iter.hasNext()) {
     System.out.println(iter.next());
   }
 }

}

 </source>
   
  
 
  

Set: 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>
   
  
 
  

Set: remove(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));
   set.remove("A");
   System.out.println(set);
 }

}

 </source>
   
  
 
  

Set: retainAll(Collection c)

   <source lang="java">

/*

---

union--------------

A B C

---

intersection--------------

A B*/ import java.util.Collection; import java.util.HashSet; import java.util.Iterator; import java.util.Set; import java.util.TreeSet; public class MainClass {

 public static void main(String[] args) {
   // Create two sets.
   Set s1 = new HashSet();
   s1.add("A");
   s1.add("B");
   s1.add("C");
   Set s2 = new HashSet();
   s2.add("A");
   s2.add("B");
   Set union = new TreeSet(s1);
   union.addAll(s2); // now contains the union
   print("union", union);
   Set intersect = new TreeSet(s1);
   intersect.retainAll(s2);
   print("intersection", intersect);
 }
 protected static void print(String label, Collection c) {
   System.out.println("--------------" + label + "--------------");
   Iterator it = c.iterator();
   while (it.hasNext()) {
     System.out.println(it.next());
   }
 }

}

 </source>
   
  
 
  

Set: 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>
   
  
 
  

Set: 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>
   
  
 
  

Set: toArray(String[] a)

   <source lang="java">

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

 public static void main(String[] args) {
   // A string array with duplicate values
   String[] data = { "A", "C", "B", "D", "A", "B", "E", "D", "B", "C" };
   System.out.println("Original array         : " + Arrays.toString(data));
   List<String> list = Arrays.asList(data);
   Set<String> set = new HashSet<String>(list);
   System.out.print("Remove duplicate result: ");
   String[] result = new String[set.size()];
   set.toArray(result);
   for (String s : result) {
     System.out.print(s + ", ");
   }
 }

}

 </source>