Hi to all, seems to be simple, but I do not find the solution: What must I write for the splitted ???? to get splitted$"3"$x and splitted$"3"$x y = c(rep(2,5),rep(3,5)) ma <- data.frame(x = 1:10, y=y ) splitted <- split(ma, ma$y) for (counter in (min(ma$y):max(ma$y))) { splitted????$x } Regards Knut