They are different animals. Scenarios where you could choose between index-based or property-based iteration don't come to mind.
Also note property-based iteration can perform much more slowly iterating proxy-based objects, and do not work on sealed non-dynamic classes. -Alex From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Josh McDonald Sent: Tuesday, December 09, 2008 3:51 PM To: [email protected] Subject: Re: [flexcoders] speed of the "for each" looping *nods* I find that it's often much easier to read when you use for..in and for each..in rather than regular for. And since you need to have a "var current = list[i]" or similar as the first line, If you only need an index to display, or it's 1-based as opposed to 0-based, using a "for [each]..in" and having the first inner line be "++idx" will be easier to read than a bunch of statements within your loop that look like: var current = foo[i+1] or msg = "you're at item #" + (i + 1) If you want to know more about for each and how it works (outside of Arrays at least), look into flash.Proxy. The documentation is a little unclear at times on Proxy, so I wrote a couple of posts on using it here: http://flex.joshmcdonald.info/2008/09/using-proxy-class-part-1_04.html http://flex.joshmcdonald.info/2008/09/using-proxy-class-part-2.html * IMHO, YMMV, (code) beauty is in the eye of the beholder, etc... =] -Josh On Wed, Dec 10, 2008 at 9:37 AM, Maciek Sakrejda <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>> wrote: Interesting. I decided to actually try my test above, and on 1000000 items, the for-each version takes ~50 milliseconds, versus ~25 milliseconds for the explicitly indexed loop. When doing some actual work in the loop (a trace), the numbers are 41.9 seconds for the for-each and 41.1 seconds for the indexed for. On a loop with a trace with 100 items, both forms take ~5 milliseconds. This is rather unscientific, but I don't have the profiler available (will it ever make it to Linux, Adobe?). So yes, it looks like for-each is a lot slower in some cases, but I'll maintain it still probably won't make a difference unless you've got a massive loop that does very little, or a deeply nested set of loops. Consider also the readability and maintainability benefits of a for-each: unless you need the index, it's just one more place to introduce bugs when refactoring, and it's cognitive cruft when trying to follow what's going on. -- Maciek Sakrejda Truviso, Inc. http://www.truviso.com -----Original Message----- From: Alex Harui <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>> Reply-To: [email protected]<mailto:[email protected]> To: [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>> Subject: RE: [flexcoders] speed of the "for each" looping Date: Tue, 9 Dec 2008 12:30:19 -0800 For each should be much slower than a basic iterator as it has to walk the object's properties. For each (var p:* in someObject) And For (var p:String in SomeObject) Probably run at the same rate. From:[email protected]<mailto:[EMAIL PROTECTED]> [mailto:[email protected]<mailto:[email protected]>] On Behalf Of Cato Paus Sent: Tuesday, December 09, 2008 5:28 AM To: [email protected]<mailto:[email protected]> Subject: [flexcoders] speed of the "for each" looping 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 ? ------------------------------------ -- Flexcoders Mailing List FAQ: http://groups.yahoo.com/group/flexcoders/files/flexcodersFAQ.txt Alternative FAQ location: https://share.acrobat.com/adc/document.do?docid=942dbdc8-e469-446f-b4cf-1e62079f6847 Search Archives: http://www.mail-archive.com/flexcoders%40yahoogroups.comYahoo! Groups Links Individual Email | Traditional -- "Therefore, send not to know For whom the bell tolls. It tolls for thee." Like the cut of my jib? Check out my Flex blog! :: Josh 'G-Funk' McDonald :: 0437 221 380 :: [EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]> :: http://flex.joshmcdonald.info/ :: http://twitter.com/sophistifunk
