RE: sort

• To: mathgroup at smc.vnet.net
• Subject: [mg30002] RE: [mg29991] sort
• From: "Harvey P. Dale" <hpd1 at nyu.edu>
• Date: Sat, 21 Jul 2001 00:49:08 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```Russ:
Suppose mat={{1,2},{2,4},{1,3},{2,1},{2,7},{1,5}}.  A simple Sort
statement (Sort[mat]) produces {{1,2},{1,3},{1,5},{2,1},{2,4},{2,7}}.  Isn't
that what you want?
There are more complicated ways to do this, of course, that give you
more control over the ordering functions.  For example, you can first sort
by the second key and then sort the resulting output by the first key.
Using the same less-than-or-equal-to operators, this would look like this:
Sort[Sort[mat,#1[[2]]<=#2[[2]]&],#1[[1]]<=#2[[1]]&].  It produces the same
output as above, but shows how you could change the ordering rule(s) if you
wish.
Best.
Harvey
Professor Harvey P. Dale
Director
National Center on Philanthropy and the Law
New York University School of Law
Room 206A
110 West 3rd Street
New York, N.Y. 10012-1074
tel: 212-998-6161
fax: 212-995-3149

-----Original Message-----
From: 	nails at asu.edu [mailto:nails at asu.edu]
To: mathgroup at smc.vnet.net
Sent:	Friday, July 20, 2001 3:29 AM
To:	mathgroup at smc.vnet.net
Subject:	[mg29991] sort

Does anybody now how to sort a matrix first by one column and then by
another column (giving priority to the first column and sorting by
second column only when there are ties in the first column).

Please respond to nails at asu.edu

Thank you,
--Russ--

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