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Subsetting indexed variable?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg36028] Subsetting indexed variable?
  • From: "Gareth J. Russell" <gjr2008 at columbia.edu>
  • Date: Tue, 13 Aug 2002 05:22:51 -0400 (EDT)
  • Organization: Columbia University
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,

I cannot seem to work out how to extract a subset of information from an
indexed variable (without generating a full list/matrix first).

For example, suppose I define:

b[1,3] = 3
b[2,3] = 7
b[2,4] = 5

And I then want to get the list of all DEFINED values of b[2,_], i.e., the
result should be {7,5}

Help appreciated!

Gareth

==========================================================
Dr. Gareth J. Russell
Columbia University
E-mail: gjr2008 at columbia.edu
==========================================================




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