Dear R user, a very simple question: I have a table like this: coor v1 v2 v3 x1 12 33 123 x2 1 123 x3 12 x4 33 1 and I'd like to tranform this matrix in presence/absence data.frame coor 1 12 33 123 x1 0 1 1 1 x2 1 0 0 1 x3 0 1 0 0 x4 1 0 1 0 Could you suggest me a direct way to do this? Thank you Giovanni