matrix(letters[1:10],nrow=5,ncol=2,byrow=FALSE) [,1] [,2] [1,] "a" "f" [2,] "b" "g" [3,] "c" "h" [4,] "d" "i" [5,] "e" "j" matrix(letters[1:10],nrow=5,ncol=2,byrow=TRUE) [,1] [,2] [1,] "a" "b" [2,] "c" "d" [3,] "e" "f" [4,] "g" "h" [5,] "i" "j"