Thank you Dimitris! I have 3D arrays of the same dimensions, so Reduce worked...
Best, Eleni On Thu, Mar 4, 2010 at 5:13 PM, Dimitris Rizopoulos < d.rizopou...@erasmusmc.nl> wrote: > do these lists contain 3D arrays of the same dimensions? If yes, then you > could use > > Reduce("+", pred.svm[[i]])[1,2,5] > > otherwise a for-loop will also be clear and efficient, e.g., > > > W <- pred.svm[[i]][[1]][1,2,5] > for (j in 2:20) { > W <- W + pred.svm[[i]][[j]][1,2,5] > } > > > I hope it helps. > > Best, > Dimitris > > > > On 3/4/2010 4:02 PM, Eleni Christodoulou wrote: > >> Dear list, >> >> I have some difficulty in manipulating list elements. More specifically, I >> am performing svm regression and have a list of lists, called pred.svm. >> The >> elements of the second list are 3D arrays. Thus I have pred.svm[[i]][[j]], >> with 1<=i<=5 and 1<=j<=20. >> I want to take the sum of the elements a specific array dimension across >> all >> j, for one i. Mathematically speaking, I want to calculate *W* as: >> >> *W = pred.svm[[i]][[1]][1,2,5] + pred.svm[[i]][[2]][1,2,5]+ >> pred.svm[[i]][[3]][1,2,5]+...+ pred.svm[[i]][[20]][1,2,5]* >> >> I have tried to apply the *lapply() *function but it seems that its >> arguments can only be vector elements of a list...Do I need to convert the >> array data to vector data? >> >> Any advice would be very welcome! >> >> Thanks a lot, >> Eleni >> >> [[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. >> >> > -- > Dimitris Rizopoulos > Assistant Professor > Department of Biostatistics > Erasmus University Medical Center > > Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands > Tel: +31/(0)10/7043478 > Fax: +31/(0)10/7043014 > [[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.