The command ?apply will easily get row means/vars (or col means/vars) e.g. my.mat<-matrix(rnorm(144),12) my.mat apply(my.mat,1,mean,na.rm=T) apply(my.mat,1,var,na.rm=T)
The functions ?rbind and ?cbind will help you add rows or columns to matrices or data frames Enjoy Wayne -----Original Message----- From: Haiyan Chen [mailto:[EMAIL PROTECTED] Sent: 18 February 2004 15:39 To: [EMAIL PROTECTED] Subject: [R] How to repeat a procedure Hello, 1. After I generate a 100x50 matrix by x3<-matrix(0,100,50);for (i in 1:100) {x1<-rpois(50, mu[i]);x2<-x1; x2[runif(50)<.01]<-0; x3[i,]<-x2}, 2. I want to calculate means and sample variances of each row and create a new matrix 100x2; 3. I then want to repeat above procedure 500 times so that eventually I will have 500 100x2 matrices. Would someone mind helping me to code 2 & 3? Thanks ahead of time. Heyen ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html KSS Ltd Seventh Floor St James's Buildings 79 Oxford Street Manchester M1 6SS England Company Registration Number 2800886 Tel: +44 (0) 161 228 0040 Fax: +44 (0) 161 236 6305 mailto:[EMAIL PROTECTED] http://www.kssg.com The information in this Internet email is confidential and m...{{dropped}} ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
