vec is being recycled column wise, so you can repeat each element the required number of times:
tmp[p,] <- rep(vec, each = length(p)) There's many ways to achieve this though, so it depends on what other variations you might want to deal with. Cheers, Mike. On Mon, Nov 29, 2010 at 2:53 PM, Bryan Hanson <han...@depauw.edu> wrote: > Hello Folks. This must be a silly question with a (not) obvious (to me) > answer. > > Consider this: > > tmp <- matrix(1:200, nrow = 20) > vec <- 300:309 > > tmp[9,] <- vec # replacing one row works fine > > p <- c(3, 11, 17) > tmp[p,] <- vec > # replacing multple rows pastes the values down a column and recycles vec. > > What I want to do is replace multiple rows simultaneously at once. I > suppose I can write a function, but this seems pretty fundamental so I feel > I must be missing some obvious alternative. I'm feeling like I'm in the > Inferno! > > TIA. Bryan > ************* > Bryan Hanson > Professor of Chemistry & Biochemistry > DePauw University, Greencastle IN USA > >> sessionInfo() > R version 2.12.0 (2010-10-15) > Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit) > > locale: > [1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8 > > attached base packages: > [1] splines datasets tools grid grDevices graphics utils > stats > [9] methods base > > other attached packages: > [1] survival_2.35-8 gridExtra_0.7 GGally_0.2.2 xtable_1.5-6 > [5] mvbutils_2.5.1 ggplot2_0.8.8 proto_0.3-8 reshape_0.8.3 > [9] ChemoSpec_1.46 seriation_1.0-2 colorspace_1.0-1 TSP_1.0-1 > [13] R.utils_1.5.3 R.oo_1.7.4 R.methodsS3_1.2.1 rgl_0.92.794 > [17] lattice_0.19-13 mvoutlier_1.4 plyr_1.2.1 > RColorBrewer_1.0-2 > [21] chemometrics_1.0 som_0.3-5 robustbase_0.5-0-1 rpart_3.1-46 > [25] pls_2.1-0 pcaPP_1.8-3 mvtnorm_0.9-92 nnet_7.3-1 > [29] mclust_3.4.6 MASS_7.3-8 lars_0.9-7 gclus_1.3 > [33] cluster_1.13.1 e1071_1.5-24 class_7.3-2 > > ______________________________________________ > 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. > -- Michael Sumner Institute for Marine and Antarctic Studies, University of Tasmania Hobart, Australia e-mail: mdsum...@gmail.com ______________________________________________ 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.
