[R] Replacing several rows of a matrix at once
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_2.35-8gridExtra_0.7 GGally_0.2.2 xtable_1.5-6 [5] mvbutils_2.5.1 ggplot2_0.8.8 proto_0.3-8reshape_0.8.3 [9] ChemoSpec_1.46 seriation_1.0-2colorspace_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_0.19-13mvoutlier_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_1.8-3mvtnorm_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.
Re: [R] Replacing several rows of a matrix at once
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.
Re: [R] Replacing several rows of a matrix at once
Hi Bryan, The reason vec gets recycled is that you are replacing more values than vec has. Just look at: tmp[p, ] this is 3 x 10 matrix, which you are trying to replace with a vector of length 10. If you want the replacement to occur without any recycling, you'll need to make vec be a matrix itself or at least a vector of length 30 (i.e., 3 * 10). Or do you want it recycled but in a different way than it is currently being recycled? (see Michael's response for that). Cheers, Josh On Sun, Nov 28, 2010 at 7:53 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. -- Joshua Wiley Ph.D. Student, Health Psychology University of California, Los Angeles http://www.joshuawiley.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.
Re: [R] Replacing several rows of a matrix at once
On 2010-11-28 19:53, Bryan Hanson 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! Since matrices in R use column-major order, transpose first: ttmp - t(tmp) ttmp[, p] - vec (ans - t(ttmp)) Peter Ehlers 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_2.35-8gridExtra_0.7 GGally_0.2.2 xtable_1.5-6 [5] mvbutils_2.5.1 ggplot2_0.8.8 proto_0.3-8reshape_0.8.3 [9] ChemoSpec_1.46 seriation_1.0-2colorspace_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_0.19-13mvoutlier_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_1.8-3mvtnorm_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. __ 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.
Re: [R] Replacing several rows of a matrix at once
Thanks to Michael, Josh and Jorge - Problem fixed. Michael's suggestion was what I needed, but I wouldn't have ever conceptualized it that way, and Jorge showed me how simple the function could be (at this hour, I was imagining it would be more work). Thanks guys. Bryan On 11/28/10 11:03 PM, Michael Sumner mdsum...@gmail.com wrote: 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. __ 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.
