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Sorting on multiple columns within a matrix

• To: mathgroup at smc.vnet.net
• Subject: [mg57819] Sorting on multiple columns within a matrix
• From: Lee Newman <leenewm at umich.edu>
• Date: Thu, 9 Jun 2005 05:18:06 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

Hello,

I can't come up with a solution to the following simple task:

-  I have a matrix, let's M={ {"Z",2,"a"},{"A",2,"k"}, {"Z",1,"z"}, 
{"A",1,"a"},{"Z",3,"k"}, {"A",3,"z"} }
-  I want to be able to sort the matrix row-wise, based on multiple 
columns, for example sort first on column 2 (ascending) and then 
secondly on column1 (ascending)

desired result:
A 1 a
Z 1 z
A 2 k
Z 2 a
A 3 z
Z 3 k

I suspect the solution involves using a pure function of some form as 
the second argument in the Sort function, but I can't figure out what 
this function should be.

Thanks,
Lee

• Follow-Ups:
  • Re: Sorting on multiple columns within a matrix
    • From: János <janos.lobb@yale.edu>