On Tue, Dec 30, 2008 at 10:21 AM, baptiste auguie <ba...@exeter.ac.uk> wrote: > I thought this was a good candidate for the plyr package, but it seems that > l*ply functions are meant to operate only on separate list elements: > > Lists are the simplest type of input to deal with because they are already > naturally > divided into pieces: the elements of the list. For this reason, the l*ply > functions don't > need an argument that describes how to break up the data structure. > > (from: plyr: divide and conquer, Hadley Wickham 2008) > > Perhaps a new case to consider?
Possibly, but here I would argue that the choice of data structure isn't quite right - if the matrices all have the same dimension, then they should be stored in an array, not a list: foo <- list(rbind(c(1,2,3),c(4,5,6)),rbind(c(7,8,9),c(10,11,12))) foo2 <- unlist(foo) dim(foo2) <- c(dim(foo[[1]]), length(foo)) Then you can use apply (or aaply) directly on that matrix: apply(foo2, c(1,2), mean) apply(foo2, c(1,2), mean, trim = 0.1) etc. Hadley -- http://had.co.nz/ ______________________________________________ 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.
