Hi, I would like to sum some specific columns in my matrix- for example, my matrix looks like this: [,1] [,2] [,3] [,4] [,5] [1,] 1 NA NA NA NA [2,] 2 1 NA 1 NA [3,] 3 2 1 2 1 [4,] 4 3 2 3 2 [5,] NA NA NA 4 3 [6,] NA NA NA 5 NA
I would like to find the sum of the first two columns, the second two columns and the last column: i.e I am left with a vector of c(16, 18, 6). I know about colSums and sum overall- I just wondered if this type of grouping can be included somehow in a vector such as c(2,2,1)? I don't really want to have to use a loop for this. Many thanks Emma -- View this message in context: http://r.789695.n4.nabble.com/Summing-over-specific-columns-in-a-matrix-tp3179400p3179400.html Sent from the R help mailing list archive at Nabble.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.