Dear R-users, I'm trying to extract the exact location of the maximum value in a vector or a matrix, meaning I want not only the maximum itself but also at which position (e.g row 6, column 12) it is located. I appreciate any suggestions. Thanks, Patrick -------------- next part -------------- A non-text attachment was scrubbed... Name: patrick.vcf Type: text/x-vcard Size: 339 bytes Desc: Card for Patrick Buetzberger Url : https://stat.ethz.ch/pipermail/r-help/attachments/20020305/e8b71fd0/patrick.vcf
Patrick Buetzberger <patrick at giub.unibe.ch> writes:> Dear R-users, > > I'm trying to extract the exact location of the maximum value in a > vector or a matrix, meaning I want not only the maximum itself but also > at which position (e.g row 6, column 12) it is located. > I appreciate any suggestions.To find which element of x is equal to the maximum of x, try which(x==max(x)) if you want the array index of the maximum of a matrix, use which(m==max(m), arr.ind=TRUE) -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Dear Patrick, What about: x <- rnorm(100) mx <- max(x) exact.location <- which(x == mx) Hopin' it helps, Laurent Laurent Gautier CBS, Building 208, DTU PhD. Student D-2800 Lyngby,Denmark tel: +45 45 25 24 85 http://www.cbs.dtu.dk/laurent On Tue, 5 Mar 2002, Patrick Buetzberger wrote:> Dear R-users, > > I'm trying to extract the exact location of the maximum value in a > vector or a matrix, meaning I want not only the maximum itself but also > at which position (e.g row 6, column 12) it is located. > I appreciate any suggestions. > Thanks, > > Patrick >-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
For a vector:> max(a1)[1] 16667> (1:length(a1))[a1==max(a1)][1] 6175 or> which.max(a1)[1] 6175 For a matrix:> a2 <- matrix(1:12,ncol=3) > a2[,1] [,2] [,3] [1,] 1 5 9 [2,] 2 6 10 [3,] 3 7 11 [4,] 4 8 12> max(a2)[1] 12> which.max(a2)[1] 12> col(a2)[,1] [,2] [,3] [1,] 1 2 3 [2,] 1 2 3 [3,] 1 2 3 [4,] 1 2 3> col(a2)[12][1] 3> row(a2)[12][1] 4 Agus Dr. Agustin Lobo Instituto de Ciencias de la Tierra (CSIC) Lluis Sole Sabaris s/n 08028 Barcelona SPAIN tel 34 93409 5410 fax 34 93411 0012 alobo at ija.csic.es On Tue, 5 Mar 2002, Patrick Buetzberger wrote:> Dear R-users, > > I'm trying to extract the exact location of the maximum value in a > vector or a matrix, meaning I want not only the maximum itself but also > at which position (e.g row 6, column 12) it is located. > I appreciate any suggestions. > Thanks, > > Patrick >-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._