Hi, You may try: x <- 1:5 set.seed(49) mat1 <- do.call(rbind,lapply(1:1000,function(y) sample(x,3)))
#or mat2 <- matrix(0,ncol=3,nrow=1000) set.seed(49) for(i in seq_len(nrow(mat2))) mat2[i,] <- sample(x,3) all.equal(mat1,mat2) #[1] TRUE #or set.seed(49) mat3 <- t(replicate(1000,sample(x,3))) all.equal(mat2,mat3) #[1] TRUE A.K. Hi, I have written a program that runs a series of calculations using random numbers, so that each time that I run the program I get a vector with different results. I need to repeat this program multiple times and combine all of the vectors into a single data frame or matrix. I am fairly certain that a "for loop" is what I need, but after digging around online and in multiple books, I am very confused about how to set up the loop. Just as an example, suppose that I want to randomly select 3 numbers from 1 to 5. I could do it using the following two lines: x <- 1:5 y <- sample(x,3) now suppose that I want to do this 1000 times, how do I set up a loop that will give me 1000 iterations of y (i.e. it will select 1000 sets of 3 values ranging from 1:5)? In other words, how do I loop y a specified number of times? Thanks for the help ______________________________________________ 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.
