rowSums((A[,1:8]==0)*A[,2:9]==1) and adjust the 8 and the 9 for the number of columns in your matrix
Ben -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Guenther, Cameron Sent: Tuesday, November 28, 2006 3:20 PM To: r-help@stat.math.ethz.ch Subject: [R] Counting zeros in a matrix Hi All, If you could help me with this problem I would greatly appreciate it. Suppose I have a matrix A: 1 1 1 1 0 1 1 1 1 1 1 1 0 1 0 1 0 0 1 0 1 0 0 1 0 0 0 1 1 0 0 0 0 1 0 0 I would like, for each row, to sum the number of times a 0 appears in front of a 1. So what I would like is to have Sum 1 1 1 1 0 1 1 1 1 1 1 1 1 0 1 0 1 0 0 2 1 0 1 0 0 1 0 0 0 2 1 1 0 0 0 0 1 0 0 1 I tried writing a function to do this but am getting mixed up in the [i,j] coding. This is just an example the real matrix is much larger. Thanks in advance. Cameron Guenther, Ph.D. 100 8th Ave. SE St. Petersburg, Fl 33701 727-896-8626 ext. 4305 [EMAIL PROTECTED] ______________________________________________ R-help@stat.math.ethz.ch 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.
