Perhaps this works for creating a new void dataframe: Newvoid = function (...) {a=c(...); m=length(a) initial=matrix(rep(NA,m),byrow=T,ncol=m) tab=data.frame(initial) colnames(tab)=a; subset(tab,F)} Josef Eschgfäller -- Josef Eschgfäller Dipartimento Matematico Universita' di Ferrara http://felix.unife.it