Hi Eliza, May be this helps: lapply(split(seq_len(nrow(AAA)),((seq_len(nrow(AAA))-1)%%12)+1),function(i) AAA[i,]) A.K.
On Tuesday, May 27, 2014 6:48 PM, eliza botto <eliza_bo...@hotmail.com> wrote: Dear R family, I have this matrix say AAA<-matrix(sample(1:240),ncol=2) I first want to combine every 13th row in both columns. precisely, starting from row-1 1,13,25,37,49,.... then starting from row-2 2,14,26,38,50 also 3,15,27,39,51 and similarly starting from row 4, row number 5, row 6... till 12th row,for both columns. so in a way we will have list of 12 matrices each with 10 rows and 2 columns. Finally, I want to calculate mean of each column of each matrix in that list, while keeping the integrity of the list intact. Kindly Advice! Thankyou very much indeed in advance. Eliza [[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.
