Replacing Part of a Matrix

*To*: mathgroup at smc.vnet.net*Subject*: [mg20250] Replacing Part of a Matrix*From*: flippy652 at my-deja.com*Date*: Fri, 8 Oct 1999 18:30:22 -0400*Sender*: owner-wri-mathgroup at wolfram.com

Hello all, I have a n x n matrix, call it A. I have a (n - 2)x(n - 2) matrix, call it B. I would like to keep the outer rows and columns of A, but repalce the inner rows and columns with thos of B to get a new C. I looked at the ReplacePart and other matrix and list manipulation rules and couldn't quite find one. I wrote a very gross module to do it. Does anyone have such a module in Mathematica they would like to share. For example, c = replace_a_b[a, b] would return the desired result. Example: A = {{1,2,3,4},{5,6,7,8},{9,10,11,12}, {13,14,15,16}} B = {{20,30,},{40,50}} C = replace_a_b[A,B], would produce: C = {{1,2,3,4},{5,20,30,8},{9,40,50,12}, {13,14,15,16}} Basically, this function just replaces the interior (n-2)x(n-2) in the larger matrix. Can anyone help? By the way, thank you to all who responded with such an easy and useful rectangular grid generator. Thank you. Wilson Figueroa flip at safebunch.com http://safebunch.com Sent via Deja.com http://www.deja.com/ Before you buy.