Re: Difference between two arrays

Newsgroups	comp.lang.javascript
Date	2014-05-31 14:59 -0700
References	<z_ydnZKbtslwbR7OnZ2dnUVZ_rGdnZ2d@westnet.com.au> <gu6Ogk5fthhTFwJG@invalid.uk.co.demon.merlyn.invalid>
Message-ID	<8fb98ef4-ceba-4573-a64c-c45cf9ebdf69@googlegroups.com> (permalink)
Subject	Re: Difference between two arrays
From	"Michael Haufe (TNO)" <tno@thenewobjective.com>

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On Wednesday, May 28, 2014 12:22:39 PM UTC-5, Dr J R Stockton wrote:
[...]
> 
> Create a third array which contains the first array once and the second
> array twice.  Then use sort() to get a fourth array from the third.
> Then do a linear scan of the fourth array looking for consecutive equal
> elements.  Singlets occur in only the first array, doublets only in the
> second, and triplets occur in both.  You can then store copies of the
> elements according to multiplicity in three more arrays.
> Of course, you do not copy elements; you only make new pointers to them.
> The method should be reasonably efficient, and extends to comparing more
> than two arrays.

- JavaScript sort is an in-place sort, so I don't know where this 4th array is coming from.
- Would you mind qualifying "reasonably efficient"? I'm not convinced of this using what I think is your approach, especially as more than two arrays are used.

Thread

Difference between two arrays Andrew Poulos <ap_prog@hotmail.com> - 2014-05-27 11:55 +1000
  Re: Difference between two arrays Denis McMahon <denismfmcmahon@gmail.com> - 2014-05-27 05:58 +0000
  Re: Difference between two arrays John C <rescattered@gmail.com> - 2014-05-27 03:34 -0700
    Re: Difference between two arrays Spamless <Spamless@Nil.nil> - 2014-05-31 06:35 -0500
      Re: Difference between two arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-05-31 14:57 +0200
        Re: Difference between two arrays Spamless <Spamless@Nil.nil> - 2014-06-01 03:43 -0500
          Re: Difference between two arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-06-01 14:01 +0200
            Re: Difference between two arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-06-01 16:53 +0200
  Re: Difference between two arrays Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-05-27 13:41 +0100
    Re: Difference between two arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-05-27 17:41 +0200
    Re: Difference between two arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-05-27 17:49 +0200
      Re: Difference between two arrays Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-05-27 17:34 +0100
        Re: Difference between two arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-05-27 19:33 +0200
          Re: Difference between two arrays Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-05-27 20:03 +0100
    Re: Difference between two arrays Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-05-27 17:16 +0100
      Re: Difference between two arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-05-27 19:29 +0200
  Re: Difference between two arrays Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-05-27 17:21 +0200
  Re: Difference between two arrays Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-05-28 18:22 +0100
    Re: Difference between two arrays Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-05-30 22:23 +0100
    Re: Difference between two arrays "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-05-31 14:59 -0700
      Re: Difference between two arrays "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-06-01 00:50 +0200
        Re: Difference between two arrays "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-05-31 16:17 -0700
          Re: Difference between two arrays "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-06-01 10:49 +0200
            Re: Difference between two arrays "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-06-01 13:37 -0700
      Re: Difference between two arrays Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-06-01 18:56 +0100

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