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Re: Extract any diagonal from a square matrix...

• To: mathgroup at smc.vnet.net
• Subject: [mg66531] Re: Extract any diagonal from a square matrix...
• From: "J Siehler" <jsiehler at gmail.com>
• Date: Fri, 19 May 2006 03:39:27 -0400 (EDT)
• References: <e3js8r$8kh$1@smc.vnet.net><e3uofj$ial$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

I'm sure everyone's past caring, but here's a solution that avoids
separate definitions for super- and subdiagonals, and behaves well with
nonsquare matrices:

diag[t_, d_] := Extract[t, Cases[Position[t, _, {2}, Heads -> False],
{x_, y_} /; y == x + d]]