Comments on: Array.sort() should not be used to shuffle an array http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/ Stephane Roucheray's trivial work and thoughts Tue, 29 Mar 2011 23:32:54 +0000 hourly 1 http://wordpress.org/?v=3.0.4 By: Programmatori del caso « Macworld Online http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/comment-page-1/#comment-380 Programmatori del caso « Macworld Online Fri, 05 Mar 2010 02:11:28 +0000 http://sroucheray.org/blog/?p=375#comment-380 [...] e spiega ai tecnicamente inclinati come andrebbe evitato. Per superprogrammatori si trova anche una descrizione teorica e pratica della [...] [...] e spiega ai tecnicamente inclinati come andrebbe evitato. Per superprogrammatori si trova anche una descrizione teorica e pratica della [...]

]]> By: Stéphane Roucheray http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/comment-page-1/#comment-373 Stéphane Roucheray Sun, 28 Feb 2010 11:11:45 +0000 http://sroucheray.org/blog/?p=375#comment-373 Not at all. The European Commission forces Microsoft to show Windows users a screen asking to choose fro a browser if they still use the one by default. The web site <a href="http://opentochoice.org" rel="nofollow">http://opentochoice.org</a> is the Mozilla website to help people make a decision. The window which will be displayed to Windows users to ask them to make their choice is a web page developed by and hosted at Microsoft's : <a href="http://www.browserchoice.eu" rel="nofollow">http://www.browserchoice.eu</a> (Not to be confused with the previous one). The Microsoft web page at <a href="http://www.browserchoice.eu" rel="nofollow">http://www.browserchoice.eu</a> should display browsers in random order. This is where they use a bad implementation of a random Algorithm. I don't think this is for anybody a way to benefit to something. It's just the result of the web spreading some bad habits and developers to appropriate them. Even those at Microsoft's. Not at all. The European Commission forces Microsoft to show Windows users a screen asking to choose fro a browser if they still use the one by default. The web site http://opentochoice.org is the Mozilla website to help people make a decision. The window which will be displayed to Windows users to ask them to make their choice is a web page developed by and hosted at Microsoft’s : http://www.browserchoice.eu (Not to be confused with the previous one). The Microsoft web page at http://www.browserchoice.eu should display browsers in random order. This is where they use a bad implementation of a random Algorithm. I don’t think this is for anybody a way to benefit to something. It’s just the result of the web spreading some bad habits and developers to appropriate them. Even those at Microsoft’s.

]]> By: georges http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/comment-page-1/#comment-372 georges Sun, 28 Feb 2010 08:53:36 +0000 http://sroucheray.org/blog/?p=375#comment-372 Stéphane, on http://opentochoice.org you posted about your page on Array.sort(). It's not clear to me why. Are you implying that Mozilla is doing something unfair with it? and how would they benefit from it??? Stéphane, on http://opentochoice.org you posted about your page on Array.sort().
It’s not clear to me why.
Are you implying that Mozilla is doing something unfair with it? and how would they benefit from it???

]]> By: Stéphane Roucheray http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/comment-page-1/#comment-369 Stéphane Roucheray Fri, 26 Feb 2010 08:09:18 +0000 http://sroucheray.org/blog/?p=375#comment-369 You right. That's intellectually weird, but well spread across the web unfortunately. You right. That’s intellectually weird, but well spread across the web unfortunately.

]]> By: Simon http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/comment-page-1/#comment-366 Simon Thu, 25 Feb 2010 20:03:25 +0000 http://sroucheray.org/blog/?p=375#comment-366 You misunderstand - the user-provided comparison function *is* deliberately broken, returning a random value in order to break the sort algorithm, trying to force it to un-sort the array instead. Even without the statistical demonstration of why it's invalid, this approach is screaming out 'bad idea' to me... You misunderstand – the user-provided comparison function *is* deliberately broken, returning a random value in order to break the sort algorithm, trying to force it to un-sort the array instead. Even without the statistical demonstration of why it’s invalid, this approach is screaming out ‘bad idea’ to me…

]]> By: Stéphane Roucheray http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/comment-page-1/#comment-365 Stéphane Roucheray Thu, 25 Feb 2010 08:04:30 +0000 http://sroucheray.org/blog/?p=375#comment-365 It's always a matter of efficiency. The comparison function is not "deliberately broken". It is built to be efficient at what it is intended to, ie sort things. Using it to shuffle things is, at a first glance, a clever way to use its built-in speediness but it turns that it's a bad idea. It’s always a matter of efficiency. The comparison function is not “deliberately broken”. It is built to be efficient at what it is intended to, ie sort things. Using it to shuffle things is, at a first glance, a clever way to use its built-in speediness but it turns that it’s a bad idea.

]]> By: Simon http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/comment-page-1/#comment-364 Simon Thu, 25 Feb 2010 03:24:21 +0000 http://sroucheray.org/blog/?p=375#comment-364 Perhaps I'm missing something, but this seems an awfully clumsy way of doing things - using a deliberately broken comparison function to make the sort do something other than sort. If you have access to a sort function and a random generator, why not just assign a large random integer to each item in the set, then sort the resulting pairs by the numeric order? Perhaps I’m missing something, but this seems an awfully clumsy way of doing things – using a deliberately broken comparison function to make the sort do something other than sort.

If you have access to a sort function and a random generator, why not just assign a large random integer to each item in the set, then sort the resulting pairs by the numeric order?

]]> By: Gabriel Hautclocq http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/comment-page-1/#comment-363 Gabriel Hautclocq Wed, 24 Feb 2010 17:12:26 +0000 http://sroucheray.org/blog/?p=375#comment-363 Simply excellent. Great explanation and good algorithms ! Simply excellent. Great explanation and good algorithms !

]]> By: David McFarlane http://sroucheray.org/blog/2009/11/array-sort-should-not-be-used-to-shuffle-an-array/comment-page-1/#comment-131 David McFarlane Mon, 30 Nov 2009 18:30:43 +0000 http://sroucheray.org/blog/?p=375#comment-131 Very nice explanation and demos! (Chanced upon this while looking for info on shuffling arrays without consecutive repeats.) Very nice explanation and demos! (Chanced upon this while looking for info on shuffling arrays without consecutive repeats.)

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