How to loop ArrayList in Java

Earlier we shared ArrayList example and how to initialize ArrayList in Java. In this post we are sharing how to iterate (loop) ArrayList in Java.

There are four ways to loop ArrayList:

  1. For Loop
  2. Advanced for loop
  3. While Loop
  4. Iterator

Lets have a look at the below example – I have used all of the mentioned methods for iterating list.

import java.util.*;
public class LoopExample {
   public static void main(String[] args) {

      ArrayList<Integer> arrlist = new ArrayList<Integer>();
      arrlist.add(14);
      arrlist.add(7);
      arrlist.add(39);
      arrlist.add(40);

      /* For Loop for iterating ArrayList */
      System.out.println("For Loop");
      for (int counter = 0; counter < arrlist.size(); counter++) { 		      
          System.out.println(arrlist.get(counter)); 		
      }   		

      /* Advanced For Loop*/ 		
      System.out.println("Advanced For Loop"); 		
      for (Integer num : arrlist) { 		      
           System.out.println(num); 		
      }

      /* While Loop for iterating ArrayList*/ 		
      System.out.println("While Loop"); 		
      int count = 0; 		
      while (arrlist.size() > count) {
	 System.out.println(arrlist.get(count));
         count++;
      }

      /*Looping Array List using Iterator*/
      System.out.println("Iterator");
      Iterator iter = arrlist.iterator();
      while (iter.hasNext()) {
         System.out.println(iter.next());
      }
   }
}

Output:

For Loop
14
7
39
40
Advanced For Loop
14
7
39
40
While Loop
14
7
39
40
Iterator
14
7
39
40

In the comment section below, Govardhan asked a question: He asked, how to iterate an ArrayList using Enumeration. Govardhan here is the code:

How to iterate arraylist elements using Enumeration interface

import java.util.Enumeration;
import java.util.ArrayList;
import java.util.Collections;
 
public class EnumExample {
 
   public static void main(String[] args) {
      //create an ArrayList object
      ArrayList<String> arrayList = new ArrayList<String>();
 
      //Add elements to ArrayList
      arrayList.add("C");
      arrayList.add("C++");
      arrayList.add("Java");
      arrayList.add("DotNet");
      arrayList.add("Perl");
 
      // Get the Enumeration object
      Enumeration<String> e = Collections.enumeration(arrayList);
 
      // Enumerate through the ArrayList elements
      System.out.println("ArrayList elements: ");
      while(e.hasMoreElements())
      System.out.println(e.nextElement());
   }
}

Output:

ArrayList elements: 
C
C++
Java
DotNet
Perl

4 comments… add one

  • Govardhan November 16, 2014, 5:42 AM

    sir how to iterate arraylist elements using Enumeration interface

    Reply
    • Chaitanya Singh November 18, 2014, 4:48 AM

      Hi Govardhan,

      I have updated the post and added the code. You can find your answer above in the post. Let me know if you have any further question.

      Reply
      • Govardhan December 5, 2014, 3:14 PM

        sir I have one more question:=
        1.How to find middle value of a linked list by single pass

        Reply
  • David tolu November 30, 2014, 7:25 PM

    how to detect duplicate values in an arrayList?

    Reply

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