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RE: Selecting Lists Without Null Results

• To: mathgroup at smc.vnet.net
• Subject: [mg69035] RE: [mg68970] Selecting Lists Without Null Results
• From: "David Park" <djmp at earthlink.net>
• Date: Sun, 27 Aug 2006 01:24:17 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

Gregory,

Use UnsameQ or =!=.

Length[Select[runsTable, (#[[14]]=!= Null) &]]

David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/

From: Gregory Lypny [mailto:gregory.lypny at videotron.ca]
To: mathgroup at smc.vnet.net


	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]]¬ Null) &]]

returns 0 when it should return 174, that is, 179 minus 5.

	Am I using the NOT operator incorrectly?

	Regards,

		Gregory