Dear R-help, I am writing some simulation code to create multiple sets of time-to-event clinical trial data (for use in meta-analysis). Within each trial, I want to apply censoring via simulation of uniform variables (with minimum zero and maximum the median outcome time for that particular trial).
I have started by pre-allocating a matrix which has 3 columns; one for trial number, one for patient number, and I want to complete the third with the results of the uniform simulation. For example, I have : n<-10 ## patients per trial trials<-3 ## 3 trials outcome<-matrix(NaN,nrow=n*trials,ncol=3) for(i in 1:trials){ outcome[,1]<-rep(1:trials,each=n) outcome[,2]<-rep(1:n) } In the third column, for each trial I want to create n sets of random draws: runif(n,0,median[i]), where median[i] is the median outcome time in that trial. median<-as.matrix(c(2,4,3),) ## for example So far I have been trying to include the following within the for loop: outcome[,3]<-runif(n,0,median[i]) But this just repeats the uniform draws from the last iteration of the loop in column 3. Can anyone advise how to replace the third column at each iteration rather than repeating? I think I can use rbind, but will this slow down my simulation? Many thanks in advance for your help. Natalie -- View this message in context: http://r.789695.n4.nabble.com/Replacing-sets-of-rows-in-matrix-within-a-loop-tp4634658.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.