I made a google group archive of current and future R-help posts at http://groups.google.com/group/r-help-archive
If you are signed-up for the R-help mailing list with a gmail account you can reply to posts through the google group pages. Note that this is not a separate mailing-list, just a copy of the original. Only posts after December 3rd 2007 will be available. I assume there are no objections to this. In case I am wrong please let me know. Vincent On 12/3/07 3:02 PM, "Rick DeShon" <[EMAIL PROTECTED]> wrote: > Hi All. > > I would like to compute a separate covariance matrix for a set of > variables for each of the levels of a factor and then compute the > average covariance matrix over the factor levels. I can loop through > this computation but I need to perform the calculation for a large > number of levels and am looking for something more elegant. To be > concrete.... > > u <- 3 > n <- 10 > > x <- rnorm((id*u)) > y <- rnorm((id*u)) > z <- rnorm((id*u)) > id <- gl(u,n) > > df <- data.frame(id,x,y,z) > df.s <- split(xxx,id) > > lcov <- lapply(df.s,cov) > lcov > > What's an efficient way to compute the average covariance matrix over > the list members in "lcov"? > > Thanks in advance, > > Rick DeShon > > ______________________________________________ > 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. > -- ______________________________________________ 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.
