Did you know ActionScript 3 introduced a new loop construct? I discovered this while doing a lot of XML manipulation with E4X, and it's really a gem.
Along with the "for..in" loop, we now have at our disposal a "for each..in" loop. The two loops are very similar in style/syntax, but there's a subtle difference. Consider the following code snippet:
var arr:Array = ["test", "test2", "test3"];
// Use a regular for in loop to access the properties in arr
for ( var i in arr ) {
trace( i );
}
// Use the new for each in loop to access the values in arr
for each ( var s:String in arr ) {
trace( s );
}
The first loop will trace values 0, 1, and 2. The for..in loop will loop over the property names in an object - in this case, we get the array indexes. In order to get the values in the array, we would have to "trace( arr[i] )".
The second loop will trace values test, test2, and test3. Notice the subtle difference here? Instead of getting the properties in an object, we get the property values. This is a handy shortcut, and is especially useful in dealing with XML in the E4X manner:
var data:XML =
12
61
hello
;
for each ( var f:XML in data.foo ) {
trace( f );
}
The above loop will out 12, 61, and hello.
Nothing earth shattering really, just something new to add to your bag of tricks... Enjoy!
2 Comments
makes debugging alot easier i think.
Posted by: 1stpixel | December 7, 2005 3:37 PM
Well that's a good one - i use that often in php. I mean, how often did you have to do a 'for (var i in n)' and all you needed was the n[i], not the i. For me: often! So that's a highly appreciated syntax addition really. :-)
Posted by: Sev | December 7, 2005 4:24 PM