Is this all you want? > j <- matrix(nrow=10,ncol=10) > k <- matrix(seq(1:50), ncol=10) > row.names(k) <- seq(2,10,by=2) > > row.names(j) <- 1:10 > j[row.names(k), ] <- k > > j [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] 1 NA NA NA NA NA NA NA NA NA NA 2 1 6 11 16 21 26 31 36 41 46 3 NA NA NA NA NA NA NA NA NA NA 4 2 7 12 17 22 27 32 37 42 47 5 NA NA NA NA NA NA NA NA NA NA 6 3 8 13 18 23 28 33 38 43 48 7 NA NA NA NA NA NA NA NA NA NA 8 4 9 14 19 24 29 34 39 44 49 9 NA NA NA NA NA NA NA NA NA NA 10 5 10 15 20 25 30 35 40 45 50 >
-----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of steven mosher Sent: Sunday, 5 September 2010 5:10 PM To: r-help Subject: [R] merging two maxtrices j<-matrix(nrow=10,ncol=10) k<-matrix(seq(1:50), ncol=10) row.names(k) <- seq(2,10,by=2) j [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [1,] NA NA NA NA NA NA NA NA NA NA [2,] NA NA NA NA NA NA NA NA NA NA [3,] NA NA NA NA NA NA NA NA NA NA [4,] NA NA NA NA NA NA NA NA NA NA [5,] NA NA NA NA NA NA NA NA NA NA [6,] NA NA NA NA NA NA NA NA NA NA [7,] NA NA NA NA NA NA NA NA NA NA [8,] NA NA NA NA NA NA NA NA NA NA [9,] NA NA NA NA NA NA NA NA NA NA [10,] NA NA NA NA NA NA NA NA NA NA k [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] 2 1 6 11 16 21 26 31 36 41 46 4 2 7 12 17 22 27 32 37 42 47 6 3 8 13 18 23 28 33 38 43 48 8 4 9 14 19 24 29 34 39 44 49 10 5 10 15 20 25 30 35 40 45 50 is there a simple way to merge j and k By the row.names in k so that row named '2' is placed in the 2nd row of j.. and so forth through 4,6,8,10 the actual example has a sparse k.. not evenly spaced so this should also be mergeable row.names(k) <- c(1,2,5,6,9) k [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] 1 1 6 11 16 21 26 31 36 41 46 2 2 7 12 17 22 27 32 37 42 47 5 3 8 13 18 23 28 33 38 43 48 6 4 9 14 19 24 29 34 39 44 49 9 5 10 15 20 25 30 35 40 45 50 [[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. ______________________________________________ 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.