You can at least get rid of the for (i in 1:200){ y[i]<-rbinom(1,1,0.8) x1[i]<-ifelse(y[i]==1,rnorm(1,mean=20, sd=2),rnorm(1,mean=16, sd=2.2)) ....
loop with the following y <- rbinom(200, 1, 0.8) y.1 <- y == 1 # get logical vector of y == 1 x1 <- numeric(200) # allocate the vector x1[y.1] <- rnorm(sum(y.1), 20, 2) x1[!y.1] <- rnorm(sum(!y.1), 16, 2.2) I don't know what else you are doing in the loops, but you should be thinking "vectorized" when using R and avoid 'for' loops since they are not the most efficient way of going things, especially if you are going to be them hunreds of times. On Thu, Jun 26, 2008 at 4:23 AM, sigalit mangut-leiba <[EMAIL PROTECTED]> wrote: > Hi, > I'm trying to do a double for loop like this: > for (k in 1:1000){ > for (i in 1:200){ > y[i]<-rbinom(1,1,0.8) > x1[i]<-ifelse(y[i]==1,rnorm(1,mean=20, sd=2),rnorm(1,mean=16, sd=2.2)) > .... > } > for (j in 1:300){ > .... > } > } > Does anyone know a good reference about double loops? > Thank you, > Sigalit > > [[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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem you are trying to solve? ______________________________________________ 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.