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MathGroup Archive 2006

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Re: Selecting Lists Without Null Results

  • To: mathgroup at smc.vnet.net
  • Subject: [mg69021] Re: [mg68970] Selecting Lists Without Null Results
  • From: "Adriano Pascoletti" <pascolet at dimi.uniud.it>
  • Date: Sun, 27 Aug 2006 01:23:41 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Gregory Lypny wrote ..
> 	I must be doing something wrong as usual.  How come I can select  
> list with elements that have the word Null in them as a result of a  
> computation, but I cannot exclude them?
> 
> I have an array called runsTable with 179 rows, and there are five  
> rows with Null in column 14.
> 
> So,
> 
> 	Length[Select[runsTable, #[[14]] == Null &]
> 
> returns 5.
> 
> But
> 
> 	Length[Select[runsTable, (#[[14]]=AC Null) &]]
> 
> returns 0 when it should return 174, that is, 179 minus 5.
> 
> 	Am I using the NOT operator incorrectly?
> 
> 	Regards,
> 
> 		Gregory
> 
Use Unsame (=!=) or Unequal (!=) instead of Not (=AC)
Adriano Pascoletti


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