Thanks to all of you for those answers, it now works and it's way faster than it used to be ;) Especially, converting my list of matrix to a 3-dimensionnal array simplifies a lot the statistics I have to run on my data :)
Thanks again, Robin 2011/12/14 Patrizio Frederic <frederic.patri...@gmail.com> > Hi robin, > I'm not sure is what you need, but that's an esthetically nice > solution (one single line without any loop :) ) > > > matrix(apply(log(cbind(as.numeric(a),as.numeric(b),as.numeric(c),as.numeric(d))),1,sd),3) > > hope it could help, > > PF > > > On Mon, Dec 12, 2011 at 5:15 PM, Robin Cura <robin.c...@gmail.com> wrote: > > Hello, > > > > I'm currently trying to convert a slow and ugly script I made, so that > it's > > faster and can be computed on a computer grid with the multicore package. > > My problem is that I don't see how to turn some loops into an > "apply-able" > > function. > > > > Here's an example of my loops : > > I got a list of dataframes (or matrices like here), and I need to browse > > each cell of those many dataframes to compute a mean (or standard > deviation > > like here). > > > > Here's a example script : > > > > a <- b <- c <- d <- result <- matrix(nrow=3, ncol=3) > > a[] <- sample.int(n=100,size=9,replace=TRUE) > > b[] <- sample.int(n=100,size=9,replace=TRUE) > > c[] <- sample.int(n=100,size=9,replace=TRUE) > > d[] <- sample.int(n=100,size=9,replace=TRUE) > > result[] <- NA > > mylist <- list(a,b,c,d) > > > > for (row in 1:3) > > { > > for (col in 1:3) > > { > > tmpList <- log(mylist[[1]][row, col]) > > for (listitem in 2:4) > > { > > tmpList <- c(tmpList, log(mylist[[listitem]][row, col])) > > } > > result[row, col] <- sd(tmpList) > > } > > } > > > > Considering I have to look at the same cell in each dataframe, I don't > > understand how I could turn this into a function, considering I need the > > row and column number to iterate. > > > > I succeeded improving my script duration a lot, but such loops are really > > long to run, considering that my lists contains like 100 dataframes, who > > all contains thousands of values. > > > > Any help would be really appreciated > > > > Thanks in advance, > > > > Robin > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > 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. > > > > -- > +----------------------------------------------------------------------- > | Patrizio Frederic, > | http://www.economia.unimore.it/frederic_patrizio/ > +----------------------------------------------------------------------- > [[alternative HTML version deleted]] ______________________________________________ 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.