If you're trying to speed up your application, you should use the
profiler. Something like the difference between a "manually" indexed for
loop and a for-each loop is almost certain to be trivial.
If you don't have the profiler, run an ad-hoc perf test by doing
something like
// we need to construct something to iterate over:
var iterations:int = 1000000;
var arr:Array = [];
for (var i:int = 0; i < iterations; i++) arr.push(i);
var dummy:int = 0;
var forBeginning:Number = new Date().getTime();
for (var j:int = 0; j < iterations; j++)
{
// we need to do something in the loop so the whole thing
// is not just optimized out (not sure if FP does this, but
// it can), but we don't want to use trace() since I/O is
// relatively expensive compared to the cost of the loop itself
dummy = arr[j];
}
trace("for loop took " + (new Date().getTime() - forBeginning) + "
milliseconds");
var forEachBeginning:Number = new Date().getTime();
for each (var k:int in arr)
{
dummy = k;
}
trace("for-each loop took " + (new Date().getTime() - forEachBeginning)
+ " milliseconds");
That should give you an idea of the difference (but run this many times
and average it, and vary the order of the loops). Also, keep in mind
that most of the time, you won't be iterating over a million items.
Bottlenecks can occur in surprising places (though they're often found
in common places too, like Container layout code). Don't try to optimize
things that *seem like* they would be slow without actually confirming
not only that they *are* slow, but that they are affecting the overall
speed or responsiveness of your application. It makes no sense to make a
10x performance improvement in one part of your code that accounts
for .01% of your application's CPU usage.
--
Maciek Sakrejda
Truviso, Inc.
http://www.truviso.com
-----Original Message-----
From: Cato Paus <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: [email protected]
Subject: [flexcoders] speed of the "for each" looping
Date: Tue, 09 Dec 2008 13:28:23 -0000
Hi, all you experts :)
I'm tying to speed up my application and I use a lot of
exsample
for (var i:int = 0; i < 5; i++)
{
trace(i);
}
so is the "for each" looping faster ?
