Search an element of Java ArrayList Example

Posted by: Instanceofjava Posted date: 5:40 PM / comment : 0 ,

1.Basic java Example program to search an element  ArrayList.

  1. package com.instanceofjavaforus;
  2. import java.util.ArrayList;
  3.  
  4. public class SearchArrayList{
  5.  
  6. public static void main(String[] args) {
  7.   
  8. //create an ArrayList object
  9.  ArrayList<Integer> arrayList = new ArrayList<Integer>();
  10.        
  11.         //Add elements to Arraylist
  12.         arrayList.add(1);
  13.         arrayList.add(2);
  14.         arrayList.add(3);
  15.         arrayList.add(4);
  16.         arrayList.add(5);
  17.         arrayList.add(6);
  18.         arrayList.add(7);
  19.         arrayList.add(8);
  20.         arrayList.add(9);
  21.         arrayList.add(10);
  22.         
  23.  /*
  24.  To check whether the specified element exists in Java ArrayList use
  25. boolean contains(Object element) method.
  26. It returns true if the ArrayList contains the specified object, false
  27. otherwise.*/
  28.        
  29.         boolean isFound = arrayList.contains(2);
  30.         System.out.println("Does arrayList contain 2 ? " + isFound);
  31.      
  32.   /*
  33.    To get an index of specified element in ArrayList use
  34.    int indexOf(Object element) method.
  35.    This method returns the index of the specified element in ArrayList.
  36.    It returns -1 if not found.
  37.   */
  38.    
  39.    int index = arrayList.indexOf(11);
  40.  
  41.  if(index == -1)
  42.     System.out.println("ArrayList does not contain 11");
  43.   else
  44.     System.out.println("ArrayList contains 4 at index :" + index);
  45.         
  46.         
  47.    int secindex = arrayList.indexOf(5);
  48.  
  49.  if(secindex== -1)
  50.       System.out.println("ArrayList does not contain 5");
  51.  else
  52.      System.out.println("ArrayList contains 5 at index :" + secindex);
  53.        
  54.  System.out.println("Size of ArrayList: "+ arrayList.size()); 
  55.  
  56.  Iterator itr=arrayList.iterator();
  57.  
  58. while (itr.hasNext()) {
  59.  
  60.  System.out.println(itr.next());
  61.  
  62.  }
  63.   
  64. }
  65. }
     



Output:

  1. Does arrayList contain 2 ? true
  2. ArrayList does not contain 11
  3. ArrayList contains 5 at index :4
  4. Size of ArrayList: 10
  5. 1
  6. 2
  7. 3
  8. 4
  9. 5
  10. 6
  11. 7
  12. 8
  13. 9
  14. 10

Java Example Program to Remove element from specified index ArrayList

Posted by: Instanceofjava Posted date: 4:47 PM / comment : 0 ,

 1.Basic java Example program to remove an element from specified index ArrayList.

  1. package com.instanceofjavaforus;
  2. import java.util.ArrayList;
  3.  
  4. public class RemoveElementArrayList{
  5.  
  6. public static void main(String[] args) {
  7.  
  8.    //create an ArrayList object
  9.         ArrayList<String> arrayList = new ArrayList<String>();
  10.        
  11.         //Add elements to Arraylist
  12.         arrayList.add("A");
  13.         arrayList.add("B");
  14.         arrayList.add("C"); 
  15.         arrayList.add("A");
  16.        
  17.   /*
  18.    To remove an element from the specified index of ArrayList use
  19.     Object remove(int index) method.
  20.     It returns the element that was removed from the ArrayList. */
  21.  
  22.     Object obj = arrayList.remove(1);
  23.      System.out.println(obj + " is removed from ArrayList");
  24.        
  25.   System.out.println("ArrayList contains...");
  26.   //display ArrayList elements using for loop
  27.     for(int index=0; index < arrayList.size(); index++)
  28.     System.out.println(arrayList.get(index));
  29.   
  30.  
  31.  }
  32. }
     


Output:

  1. B is removed from ArrayList
  2. ArrayList contains...
  3. A
  4. C
  5. A

     
 2.Basic java Example program to remove all elements from ArrayList.

  1. package com.instanceofjavaforus;
  2. import java.util.ArrayList;
  3.  
  4. public class RemoveAllElementArrayList{
  5.  
  6. public static void main(String[] args) {
  7.  
  8.    //create an ArrayList object
  9.         ArrayList<String> arrayList = new ArrayList<String>();
  10.        
  11.         //Add elements to Arraylist
  12.         arrayList.add("A");
  13.         arrayList.add("B");
  14.         arrayList.add("C"); 
  15.         arrayList.add("A");
  16.        
  17.  
  18. System.out.println("Size of ArrayList before removing elements : "+ arrayList.size());
  19.  
  20. /*
  21. To remove all elements from the ArrayList we need to use
  22. void clear() method.
  23. */
  24. arrayList.clear();
  25. System.out.println("Size of ArrayList after removing elements : "+ arrayList.size());  
  26.  
  27.  }
  28. }
     
Output:

     
  1. B is removed from ArrayList
  2. ArrayList contains...
  3. A
  4. C
  5. A

Basic Java program to Remove specified element from TreeSet example

Posted by: Instanceofjava Posted date: 3:20 PM / comment : 0 ,

1.Basic java example program to remove specified  element from treeset.

  1. package com.TreeSetExamplePrograms;

  3. public Class TreeSetRemoveDemo{ 
  5. import java.util.TreeSet;
  6.  
  7. public static void main(String args[]) {
  8. //create TreeSet object
  9.  
  10. TreeSet<Integer> treeSet = new TreeSet<Integer>();
  11.            
  12.    //add elements to TreeSet object
  13. treeSet.add(11);
  14. treeSet.add(12);
  15. treeSet.add(13);
  16.  
  17. System.out.println("TreeSet before removal : " + treeSet);
  18.            
  19.  /*
  20.  To remove an element from Java TreeSet object use,
  21.  boolean remove(Object o) method.
  22.  This method removes an element from TreeSet if it is present and returns
  23. true. Otherwise remove method returns false.
  24.  */
  25.            
  26.    boolean isRemoved = treeSet.remove(13);
  27.    System.out.println("Was 13 removed from TreeSet ? " + isRemoved);
  28.            
  29.   System.out.println("TreeSet elements after removal : " + treeSet);
  30.           
  31.  
  32. }
  33. }


Output:

  1. TreeSet before removal : [11, 12, 13]
  2. Was 13 removed from TreeSet ? true
  3. TreeSet elements after removal : [11, 12]


Remove all elements from Java TreeSet example:

1.Basic java example program to remove all elements from treeset.


  1. package com.TreeSetExamplePrograms;

  3. public Class TreeSetRemoveDemo{ 
  5. import java.util.TreeSet;
  6.  
  7. public static void main(String args[]) {
  8. //create TreeSet object
  9.  
  10. TreeSet<Integer> treeSet = new TreeSet<Integer>();
  11.            
  12.    //add elements to TreeSet object
  13. treeSet.add(11);
  14. treeSet.add(12);
  15. treeSet.add(13);
  16.  
  17. System.out.println("TreeSet before removal : " + treeSet);
  18.            
  19.  treeSet.clear();
  20. System.out.println("TreeSet after removal : " + treeSet);
  21.            
  22.  /*
  23.  To check whether TreeSet contains any elements or not use
  24.  boolean isEmpty() method.
  25.  isEmpty() method returns true if the TreeSet does not contains any elements
  26.  otherwise returns false.
  27.  */
  28.  
  29.  System.out.println("Is TreeSet empty ? " + treeSet.isEmpty());              
  30.  
  31. }
  32. }




Output:

  1. TreeSet before removal : [11, 12, 13]
  2. TreeSet after removal : []
  3. Is TreeSet empty ? true

Sort employee object in descending order using comparable and TreesSet

Posted by: Instanceofjava Posted date: 5:09 PM / comment : 0 ,

1.Basic Java example program sort student object descending order by id using treeset

  1. package com.TreeSetExamplePrograms;

  3. public Class Employee Implements Comparable<Employee>{ 

  5.     String name;
  6.     int id;
  7.     
  8.     public String getName() {
  9.         return name;
  10.     }
  11.  
  12.     public void setName(String name) {
  13.         this.name = name;
  14.     }
  15.  
  16.     public int getId() {
  17.         return id;
  18.     }
  19.  
  20.     public void setId(int id) {
  21.         this.id = id;
  22.     }
  23.  
  24.     Employee (String name, int id){
  25.         this.name=name;
  26.         this.id=id;
  27.     }
  28.  
  29.     @Override    public int compareTo(Employee obj) {
  30.         if (this.getId() == obj.getId()) return 0;
  31.         else
  32.         
  33.         if (this.getId() < obj.getId()) return 1;
  34.         else return -1;
  35.             
  36. }
  37.  
  38. }



  1. package com.TreeSetExamplePrograms;

  3. public Class Test{ 
  5. public static void main(String args[]) {
  6. //create TreeSet object
  7.  
  8. TreeSet<Employee> treeSet = new TreeSet<Employee>();     
  9.      
  10.        //add elements to TreeSet
  11.     treeSet.add(new Employee("abc",1));
  12.     treeSet.add(new Employee("xyz",2));
  13.     treeSet.add(new Employee("ssd",3));
  14.     treeSet.add(new Employee("ert",4));
  15.          
  16.     Iterator itr = treeSet.iterator();
  17.  
  18.  while(itr.hasNext()){
  19.  
  20.      Employee obj= (Employee)itr.next();
  21.      System.out.println(obj.getName()+"  "+obj.getId()); 

  23.   }         

  25. }
  26. }



Output:

  1. ert  4
  2. ssd  3
  3. xyz  2
  4. abc  1 

Get lowest and highest value stored in Java TreeSet example

Posted by: Instanceofjava Posted date: 4:16 PM / comment : 0 ,

1.Basic Java example program get lowest and highest values from treeset

  1. package com.TreeSetExamplePrograms;

  3. public Class TreeSetGetLowestAndHighestDemo{ 
  5.  
  6. public static void main(String args[]) {
  7. //create TreeSet object
  8.  
  9.  
  10.  TreeSet<Integer> treeSet = new TreeSet<Integer>();
  11.        
  12.  //add elements to TreeSet
  13.   treeSet.add(1);
  14.   treeSet.add(3);
  15.   treeSet.add(2);
  16.   treeSet.add(5);
  17.   treeSet.add(6);
  18.   treeSet.add(7);
  19.   treeSet.add(8);
  20.   treeSet.add(9);
  21.   treeSet.add(10);
  22.           
  23.  System.out.println(treeSet);
  24.           
  25.  System.out.println("First element in treeset : " + treeSet.first());           
  26.    
  27.  System.out.println("Last element in treeste" + treeSet.last()); 


  30. }
  31. }


Output:


  1. [1, 2, 3, 4, 5, 6, 7, 8, 9,10]
  2. First element in treeset :1
  3. Last element in treeset :10
2.Basic Java example program print elements of treeset using iterator


  1. package com.TreeSetExamplePrograms;

  3. public Class TreeSetDemo{ 
  5.  
  6. public static void main(String args[]) {
  7. //create TreeSet object
  8.  
  9.  TreeSet<String> treeSet = new TreeSet<String>();
  10.  
  11.    //add elements to TreeSet
  12.     treeSet.add("I");
  13.     treeSet.add("N");
  14.     treeSet.add("S");
  15.     treeSet.add("T");
  16.     treeSet.add("A");
  17.     treeSet.add("N");
  18.     treeSet.add("C");
  19.     treeSet.add("E");
  20.           
  21.     treeSet.add("O");
  22.     treeSet.add("F");
  23.   
  24. Iterator itr = treeSet.iterator();
  25. while(itr.hasNext()){
  26.              System.out.println(itr.next());
  27. }

  29. }
  30. }




Output:

  1. A
  2. C
  3. E
  4. F
  5. I
  6. N
  7. O
  8. S
  9. T

Get Size of Java TreeSet Example

Posted by: Instanceofjava Posted date: 3:45 PM / comment : 0 ,

1.Basic Java example program get size of treeset


  1. package com.TreeSetExamplePrograms;

  3. public Class TreeSetGetSizeDemo{ 
  5.  
  6. public static void main(String args[]) {
  7. //create TreeSet object
  8.  
  9.  TreeSet<String> treeSet = new TreeSet<String>();
  10.  
  11.    //add elements to TreeSet
  12.     treeSet.add("I");
  13.     treeSet.add("N");
  14.     treeSet.add("S");
  15.     treeSet.add("T");
  16.     treeSet.add("A");
  17.     treeSet.add("N");
  18.     treeSet.add("C");
  19.     treeSet.add("E");
  20.           
  21.     treeSet.add("O");
  22.     treeSet.add("F");
  23.           
  24.     System.out.println(treeSet);
  25.           
  26.    System.out.println("Size of TreeSet  : " + treeSet.size());           
  27.     //remove one element from TreeSet using remove method
  28.  
  29.      treeSet.remove("A");
  30.  
  31.  System.out.println("Size of TreeSet after removal of element A : " + treeSet.size()); 
  32.  System.out.println(treeSet);

  34. }
  35. }



Output:


  1. [A, C, E, F, I, N, O, S, T]
  2. Size of TreeSet  : 9
  3. Size of TreeSet after removal of element A : 8
  4. [C, E, F, I, N, O, S, T]

Java Program to convert Treesrt to an interger array

Posted by: Instanceofjava Posted date: 3:27 PM / comment : 0 ,

1.Basic Java program to copy all elements of treeset to an array


  1. package com.TreeSetExamplePrograms;

  3. public Class TreeSetDemo{ 
  5.  
  6. public static void main(String args[]) {
  7. //create TreeSet object
  8.  TreeSet<Integer> treeSet = new TreeSet<Integer>();
  9.        
  10.  //add elements to TreeSet
  11.   treeSet.add(1);
  12.   treeSet.add(3);
  13.   treeSet.add(2);
  14.   treeSet.add(5);
  15.   treeSet.add(6);
  16.   treeSet.add(7);
  17.   treeSet.add(8);
  18.   treeSet.add(9);
  19.   treeSet.add(10);
  20.         
  21.    Object[] objArray = treeSet.toArray();
  22.      //display contents of Object array
  23.  
  24.    System.out.println("TreeSet elements are copied into an Array. Now Array Contains..");
  25.  
  26.   for(int index=0; index < objArray.length ; index++)
  27.       System.out.println(objArray[index]);
  28.          
  29. }
  30. }


Output:


  1. TreeSet elements are copied into an Array. Now Array Contains..
  2. 1
  3. 2
  4. 3
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10

 2.Java example program to Convert treeset to integer array

Copy all elements of Java TreeSet to an Object Array

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