A <- matrix(rnorm(16)4,4) o <- c(1,3,2,4) A[o,o]
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Zhang Yanwei - Princeton-MRAm Sent: Thursday, August 07, 2008 10:31 AM To: r-help@r-project.org Subject: [R] Switch two rows in a matrix Hi all, I have a 4 by 4 matrix, and I want to switch row 2 and row 3 first, then switch column 2 and column 3. Is there an easy way to do it? The following is a tedious way to get what I want. But I wonder if there is a way to simplify this. > a=matrix(rnorm(16),4,4) > a [,1] [,2] [,3] [,4] [1,] 0.33833811 -0.9422273 -0.06181611 -1.8346134 [2,] -0.68167996 0.2004836 0.71079887 -1.1590184 [3,] 0.07811688 0.1338694 -1.61262688 0.2988365 [4,] 0.21869786 -1.6356661 -0.13694344 -1.2121355 > b=a > b[2,]=a[3,] > b[3,]=a[2,] > b [,1] [,2] [,3] [,4] [1,] 0.33833811 -0.9422273 -0.06181611 -1.8346134 [2,] 0.07811688 0.1338694 -1.61262688 0.2988365 [3,] -0.68167996 0.2004836 0.71079887 -1.1590184 [4,] 0.21869786 -1.6356661 -0.13694344 -1.2121355 > c=b > c[,2]=b[,3] > c[,3]=b[,2] > c [,1] [,2] [,3] [,4] [1,] 0.33833811 -0.06181611 -0.9422273 -1.8346134 [2,] 0.07811688 -1.61262688 0.1338694 0.2988365 [3,] -0.68167996 0.71079887 0.2004836 -1.1590184 [4,] 0.21869786 -0.13694344 -1.6356661 -1.2121355 Sincerely, Yanwei Zhang Department of Actuarial Research and Modeling Munich Re America Tel: 609-275-2176 Email: [EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]> [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. -------------------------------------------------------- This message w/attachments (message) may be privileged, confidential or proprietary, and if you are not an intended recipient, please notify the sender, do not use or share it and delete it. Unless specifically indicated, this message is not an offer to sell or a solicitation of any investment products or other financial product or service, an official confirmation of any transaction, or an official statement of Merrill Lynch. Subject to applicable law, Merrill Lynch may monitor, review and retain e-communications (EC) traveling through its networks/systems. The laws of the country of each sender/recipient may impact the handling of EC, and EC may be archived, supervised and produced in countries other than the country in which you are located. This message cannot be guaranteed to be secure or error-free. This message is subject to terms available at the following link: http://www.ml.com/e-communications_terms/. By messaging with Merrill Lynch you consent to the foregoing. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
