On Mon, Nov 26, 2007 at 04:35:53PM +0100, Niccolò Bassani wrote: > Dear R-users, > I'm posting a problem I already asked help for some time ago, because I'm > facing that problem once again and even because now, reading that old > e-mail, and the answer recevied, I understand I've not made myself clear. > > Here's the question: I need to create an empty list of a specific length to > fill it with a quite large amount of square matrices, which is 602. The > question is that these matrices are created inside a for cycle, and I do not > know how to recall all of them one by one, except by creating an empty list > before the cycle, than assigning for each value of the i index the amtrix > computed to the first element of the empty list. > The fact is that: i've trided to create an empty list with > > vector("list",602) > > and then putting it in a cycle, but it didn't work. This is the cycle I've > used. To prove it works (and then the cycle itself is not a problem) there's > also the output (i.e. the last square matrix computed). > > for (i in unique(elio2$id)){ > sub.mu <- exp.mu[exp.mu$id==i,] > D <- matrix(0,nrow( sub.mu),nrow(sub.mu)) > diag(D) <- sub.mu$deriv.link > A <- mat.cov[1:nrow(D),1:nrow(D)] > R <- corstr[1:nrow(D),1:nrow(D)] > W <- solve(D)%*%solve(sqrt(A))%*%solve(R)%*%solve(sqrt(A))%*%solve(D) > } > > > W > [,1] [,2] [,3] [,4] > [1,] 3.492489e+02 -7.9324883721 0.0006286788 -0.0031046240 > [2,] -7.932488e+00 17.4974625191 -1.7575467817 0.0001403319 > [3,] 6.286788e-04 -1.7575467817 17.3227959738 -1.7529916860 > [4,] -3.104624e-03 0.0001403319 -1.7529916860 17.2279244622 > > > > Does anyone knows how to insert each and every matrix like the one above in > a "omnicomprehensive" list? That's because I've to use a function requiring > me to have the matrices I need inside a list. > Thanks in advance, hope it's not a too much stupid problem! > niccol? >
you seem to have all the ingredients, so where is the problem? it's probably not really faster to preallocate this (moderately long) list. so something like, e.g. matlist <- list() for (i in 1:3) { matlist[[i]] = matrix(i, 2, 2) } should do what you want: create a list of matrices. joerg ______________________________________________ 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.