Dear Elisa, Try this: el<- matrix(1:100,ncol=20) set.seed(25) el1<- matrix(sample(1:100,20,replace=TRUE),ncol=1)
In the example you showed, there were no column names. list(el[,sort(el1)[1:3]],sort(el1,index.return=TRUE)$ix[1:3]) #[[1]] # [,1] [,2] [,3] #[1,] 31 61 71 #[2,] 32 62 72 #[3,] 33 63 73 #[4,] 34 64 74 #[5,] 35 65 75 # #[[2]] #[1] 9 5 3 A.K. ________________________________ From: eliza botto <eliza_bo...@hotmail.com> To: "smartpink...@yahoo.com" <smartpink...@yahoo.com> Sent: Thursday, April 25, 2013 9:54 AM Subject: connecting matrices Dear Arun, [text file contains the exact format] Although the last codes were absolutely correct and worked the way i want them to. I have an additional cover-up question. Suppose i have a matrix "el"....... here i show you only some part of that matrix so that codes can work faster. >el [,595586] [,595587] [,595588] [,595589] [,595590] [,595591] [,595592] [,595593] [,595594] [,595595] [,595596] [,595597] [,595598] [,595599] [,595600] [,595601] [1,] 55 55 55 55 55 55 55 55 55 55 56 56 56 56 56 56 [2,] 59 59 59 59 59 59 60 60 60 61 57 57 57 57 57 57 [3,] 60 60 60 61 61 62 61 61 62 62 58 58 58 58 58 59 [4,] 61 62 63 62 63 63 62 63 63 63 59 60 61 62 63 60 [,595602] [,595603] [,595604] [,595605] [,595606] [,595607] [,595608] [,595609] [,595610] [,595611] [,595612] [,595613] [,595614] [,595615] [,595616] [,595617] [1,] 56 56 56 56 56 56 56 56 56 56 56 56 56 56 56 56 [2,] 57 57 57 57 57 57 57 57 57 58 58 58 58 58 58 58 [3,] 59 59 59 60 60 60 61 61 62 59 59 59 59 60 60 60 [4,] 61 62 63 61 62 63 62 63 63 60 61 62 63 61 62 63 In connection to this matrix, there is another matrix which contains coordination values for each of the column of matrix "el" >el1 [595586,] 5.67 [595587,] 55.90 [595588,] 515 [595589,] 755 [595590,] 955 [595591,] 5.95 [595592,] 575 [595593,] 505 [595594,] 505 [595595,] 515 [595596,] 5612 [595597,] 506 [595598,] 576 [595599,] 5126 [595600,] 5216 [595601,] 5666 [595602,] 526 [595603,] 5.6 [595604,] 156 [595605,] 4556 [595606,] 5556 [595607,] 1256 [595608,] 1256 [595609,] 8756 [595610,] 5906 [595611,] 789 [595612,] 5006 [595613,] 1256 [595614,] 3356 [595615,] 7756 [595616,] 4456 [595617,] 3356 What i want in the end is a list of two elemens containing the 10 column of "el" which have the lowest values in matrix "el1". More precisely [[1]] [,595603][,595586][595591,] 565555 575959 596062 626163 [[2]] 5.65.675.95 is it possible to carry out such operation?? thanks for your help Elisa ______________________________________________ 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.