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Re: Initialize multi-dimensional array

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In comp.lang.javascript message <3g81i7l6qma04ij6jsef0hjprjochsvq4q@4ax.
com>, Thu, 26 Jan 2012 11:56:11, Ross McKay <au.org.zeta.at.rosko@invali
d.invalid> posted:

>On Wed, 25 Jan 2012 19:33:41 +0000, Dr J R Stockton wrote:
>
>>[...] A while loop counting down
>>is probably shorter & faster than a for loop counting up, [...]
>
>No.
>
>http://jsperf.com/caching-array-length/4


I prefer to rely on my own tests, done with a large enough loop for time
to begin to matter.

var A, J, K_ = 777 // increase     v put code in those
D0_ = new Date()
Q_ = K_ ;
D1_ = new Date()
Q_ = K_ ; while (Q_--) { }
D2_ = new Date()
Q_ = K_ ; while (Q_--) { A = [] ; J = K_ ; while (--J) A[J] = J }
D3_ = new Date()
Q_ = K_ ; while (Q_--) { A = [] ; for (J = 0 ; J < K_ ; J++) A[J] = J }
D4_ = new Date()
Q_ = [D1_-D0_, D2_-D1_, D3_-D2_, D4_-D3_] // times // Demo 6

The while loop is clearly shorter.  And I find it faster in three
browsers out of five.

-- 
 (c) John Stockton, Surrey, UK.  ?@merlyn.demon.co.uk   Turnpike v6.05   MIME.
   Web  <http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
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Initialize multi-dimensional array Archos <raul.san@sent.com> - 2012-01-24 15:09 -0800
  Re: Initialize multi-dimensional array Denis McMahon <denismfmcmahon@gmail.com> - 2012-01-25 09:56 +0000
  Re: Initialize multi-dimensional array Andreas Bergmaier <andber93@web.de> - 2012-01-25 11:48 +0100
    Re: Initialize multi-dimensional array Archos <raul.san@sent.com> - 2012-01-25 04:37 -0800
      Re: Initialize multi-dimensional array Richard Cornford <Richard@litotes.demon.co.uk> - 2012-01-25 06:35 -0800
    Re: Initialize multi-dimensional array Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-01-25 19:39 +0100
      Re: Initialize multi-dimensional array Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-01-28 01:42 +0100
  Re: Initialize multi-dimensional array "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2012-01-25 09:38 -0800
  Re: Initialize multi-dimensional array Dr J R Stockton <reply1204@merlyn.demon.co.uk> - 2012-01-25 19:33 +0000
    Re: Initialize multi-dimensional array Ross McKay <au.org.zeta.at.rosko@invalid.invalid> - 2012-01-26 11:56 +1100
      Re: Initialize multi-dimensional array Dr J R Stockton <reply1204@merlyn.demon.co.uk> - 2012-01-27 20:09 +0000

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