new for loop syntax

[Max Vandenburg]

while im familiar with the regular for-loop i.e.

for (initialization; test-expression; update-expression)
{
   // some code here
}

i recently come accross a for loop that looked like the following...

for ( x : y )
{
   // some code
}

the above confuses me, can any one explain how the latter for-loop works?

[Keith Lynn]

The enhanced for-loop is a new construct that does what the foreach construct does in other languages.

It allows you to step through an array or collection without all the syntax of a normal for loop.

Here is an example of using the new for loop.

import java.util.*;
 
public class Test {
   
   public static void main(String[] args) {
      int[] numbers = {1,2,3,4,5};
 
      List<String> list = new ArrayList<String>();
 
      list.add("Fred");
      list.add("Esther");
      list.add("Grady");
      list.add("Lamont");
      list.add("Bubba");
      list.add("Donna");
 
      for (int number : numbers)
         System.out.println(number);
 
      for (String name : list)
         System.out.println(name);
 
   }
 
}

The first loop says, for each int in the array numbers, print the int.

The second for loops says, for each String in the list, print the String.

[Mike Noel]

It is an enhanced for loop that was introduced with java 5. You can think of it like a foreach (if you're familiar with foreach from scripting languages).

Check out http://java.sun.com/developer/technicalArticles/releases/j2se15langfeat/index.html

for some info on that.

[Max Vandenburg]

Thanks Guys

[Tony Morris]

Originally posted by Keith Lynn:
It allows you to step through an array or collection without all the syntax of a normal for loop.

s/collection/java.lang.Iterable
Also note that the index is not available within the loop.