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Message-ID: <3003096.SPkdTlGXAF@PointedEars.de>
From: Thomas 'PointedEars' Lahn <PointedEars@web.de>
Reply-To: Thomas 'PointedEars' Lahn <cljs@PointedEars.de>
Organization: PointedEars Software (PES)
Date: Wed, 23 Nov 2011 21:33:26 +0100
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Subject: Re: Create a multi-dimensional array
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.javascript:8572

Denis McMahon wrote:

> var a5 = new Array(2);
> for (var i=0; i<2; i++)
> {
> a5[i]=new Array(2);
> for (var j=0; j<2; j++) a5[i][j]=new Array(2);
> }

Using arguments for the Array constructor is pointless here and error-prone.  
For that matter, using the Array constructor is unnecessary and potentially 
error-prone.  Use the Array initializer instead; it is most certainly 
ubiquitous by now [1]:

  var a5 = [];
  for (var i = 0; i < 2; ++i)
  {
    a5[i] = [];
    for (var j = 0; j < 2; ++j)
    {
      a5[i][j] = [];
    }
  }

Note that you can save memory if you do not create all potentially needed 
Array instances, but you have to pay for that with a bit of runtime (tests 
before access whether there already is an Array instance reference 
assigned).


PointedEars
___________
[1] <http://PointedEars.de/es-matrix/#!>
-- 
Danny Goodman's books are out of date and teach practices that are
positively harmful for cross-browser scripting.
  -- Richard Cornford, cljs, <cife6q$253$1$8300dec7@news.demon.co.uk> (2004)