what is the difference between the two matrix B and C? > B m n 1 1 2 2 7 8 > C <- cbind(x=A[, 1], n=B[, 2]) > C x n [1,] 1 2 [2,] 3 8 For B, it use 1 and 2 to indicate rows while C use[1,] and [2,] On 3/23/06, Jacques VESLOT <jacques.veslot at cirad.fr> wrote: > C <- cbind(x=A[, 1], n=B[, 2]) > > >