Creation matrices with a loop in R

Question

Hi i would like to create 15 Matrices with different columns,i tried this code

for(i in 1:15){Di=matrix(0,i,1000)}
for(i in 1:15){for(k in 1:i){for(j in 1:1000){Di[k,j]=runif(1,-1,1)}}}

but Di did not create D1,D2 vs. matrices for me Di stayed as one whole matrix, how can I create 15 different matrices?

Answer 1

You should use a list for this:

 l <- vector(mode="list", length=15)

 for (i in seq(along=l)) {
   l[[i]] <- matrix(runif(i*1000, -1, 1), nrow=1000, ncol=i)
 }