In section 12.6.4, "The for-in statement", of the ECMA-262 spec, it says
The mechanics of enumerating the properties (step 5 in the first algorithm, step 6 in the second) is implementation dependent. I don't see anything in the spec about Array being an exception and having a guaranteed for-in order. So I think an Array or ArrayCollection implementation is free to execute a for-in loop in any order it wants. Gordon Smith Adobe Flex SDK Team From: flexcoders@yahoogroups.com [mailto:flexcod...@yahoogroups.com] On Behalf Of Alex Harui Sent: Thursday, December 11, 2008 11:33 AM To: flexcoders@yahoogroups.com Subject: RE: [flexcoders] Re: speed of the "for each" looping Funny. I didn't realize we were talking about iterating arrays with for..in until just now. I don't think we do that in Flex code. If the docs say arrays will iterate via for..in in index order then I'd probably trust that, especially if you stuff your arrays in index order From: flexcoders@yahoogroups.com [mailto:flexcod...@yahoogroups.com] On Behalf Of Dave Cragg Sent: Thursday, December 11, 2008 3:08 AM To: flexcoders@yahoogroups.com Subject: Re: [flexcoders] Re: speed of the "for each" looping Could you clarify this? Does this non-guarantee apply to numerically indexed arrays and ArrayCollections too? Or just to associative arrays and object properties? The docs imply that the order is maintained by for...in with numerically indexed arrays. It would be a big change if that were not the case. Cheers Dave On 10 Dec 2008, at 23:00, Gordon Smith wrote: So don't use for..in or for each... in if you care about the enumeration order. It could very possibly change in future versions of the Flash Player. &n! bsp; &nbs! p; Gordon Smith Adobe Flex SDK
