How to loop / iterate a List in Java

Here i show you four ways to loop a List in Java.

  1. Iterator loop
  2. For loop
  3. For loop (Adcance)
  4. While loop
package com.mkyong.core;
 
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
 
public class ArrayToList {
     public static void main(String[] argv) {
 
	String sArray[] = new String[] { "Array 1", "Array 2", "Array 3" };
 
	// convert array to list
	List<String> lList = Arrays.asList(sArray);
 
	// iterator loop
	System.out.println("#1 iterator");
	Iterator<String> iterator = lList.iterator();
	while (iterator.hasNext()) {
		System.out.println(iterator.next());
	}
 
	// for loop
	System.out.println("#2 for");
	for (int i = 0; i < lList.size(); i++) {
		System.out.println(lList.get(i));
	}
 
	// for loop advance
	System.out.println("#3 for advance");
	for (String temp : lList) {
		System.out.println(temp);
	}
 
	// while loop
	System.out.println("#4 while");
	int j = 0;
	while (j < lList.size()) {
		System.out.println(lList.get(j));
		j++;
	}
    }
}

Output

#1 iterator
Array 1
Array 2
Array 3
#2 for
Array 1
Array 2
Array 3
#3 for advance
Array 1
Array 2
Array 3
#4 while
Array 1
Array 2
Array 3
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mkyong
Founder of Mkyong.com and HostingCompass.com, love Java and open source stuff. Follow him on Twitter, or befriend him on Facebook or Google Plus. If you like my tutorials, consider make a donation to these charities.

Comments

  • http://bangarus.blogspot.com Chaithanya Bangaru

    for (int i = 0; i < lList.size(); i++) {
    The above line can be replaced with

    int listSize = lList.size();
    for (int i = 0; i < listSize; i++) {

    Thus avoiding the size method check in every iteration..this achieves great performance if you have a large list..

  • Krishnamoorthy

    Thanks man.. This helped a lot

  • Mark

    @r30:

    He showed that one already as his #3 loop “for loop advance”

    // for loop advance
    System.out.println(“#3 for advance”);
    for (String temp : lList) {
    System.out.println(temp);
    }

  • raj

    i wanto display string ABC-123 in CBA-321 format

  • Amar

    i wanto display ABC-123 in CBA-321 format

  • http://www.rajneesh.me/ Rajneesh

    Thanks for list implementaion trying one for my ibatis project.

  • r30

    4. For-each loop (java5 feature):

    //for-each loop
    for (String element : lList) // or sArray
    {
    System.out.println( element );
    }