The for-in and for-each loops are convenient and likely to be the loops you use most. For this reason alone you should make sure you know what you can and can’t do with them. Here’s one thing I just found can save me some typing and some bloat.

Situations like this come up all the time:

// Loop over some relative URLs
for each (var url:String in urls)
    var temp:String = url;
    // Make relative URL absolute
    temp = "" + url + "?";
    // Add query string parameters
    for each (var query:Object in queries)
        temp += query.key + "=" + query.val + "&";
    // Hack off the last "&"
    temp = temp.substr(0, temp.length-1);

But do you need the temp variable or can you use url? Is it safe to change the iterator variable? The answer is a comforting and clean “yes”! Changing the iterator will not alter the iteration of the loop in any way.

With that in mind, why not start your week off by rewriting a for-in or for-each loop where you needlessly made a temporary variable? Then repent of temporary variables and write cleaner, less bloated loops from now on. :)