HI, May be this helps you (if I understand it correctly): set.seed(1) mat1<-matrix(sample(1:500,160,replace=TRUE),ncol=16) res<-do.call(rbind,lapply(1:ncol(mat1[,-16]),function(i) median(sort(stack(as.data.frame(mat1[,c(i,16)]))[,1])))) res # [,1] #[1,] 239.0 #[2,] 238.0 #[3,] 181.5 #[4,] 244.5 #[5,] 265.0 #[6,] 212.0 #[7,] 228.5 #[8,] 233.0 #[9,] 182.5 #[10,] 239.5 #[11,] 233.5 #[12,] 220.0 #[13,] 235.0 #[14,] 259.0 #[15,] 227.0
A.K. ----- Original Message ----- From: eliza botto <eliza_bo...@hotmail.com> To: "r-help@r-project.org" <r-help@r-project.org> Cc: Sent: Monday, October 15, 2012 8:20 AM Subject: [R] median between matrix column Dear useRs, 1. how to calculate single median value for two columns of a matrix? 2. i have a matrix of 16 columns and 365 rows, how to calculate median between columns 1 and 16, 2 and 16, 3 and 16, 4 and 16, 5 and 16 till 15th column. is there a loop command to do the said operation? regards 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.
