Hi R-help,
I am trying to find a way to select five highest values in data frame according some variable. I will demonstrate: c X1 X2 1 1 1 2 1 2 3 1 3 4 1 4 5 1 5 6 1 6 7 1 7 8 1 8 9 1 9 10 1 10 11 2 11 12 2 12 13 2 13 14 2 14 15 2 15 16 2 16 17 2 17 18 2 18 19 2 19 20 2 20 21 2 21 22 2 22 23 2 23 24 2 24 25 2 25 So I would like to select a rows with higest values of X2 inside X1. Expected result should be: X1 X2 1 10 1 9 1 8 1 7 1 6 2 25 2 24 2 23 2 22 2 21 I first oreded the data frame using c=c[with(c,order(X1,-X2)),] but I need a help to select highes five. It is easy to select when I have just 2 unique values of X1 but what is if I have 500 unique values in X1? Thanks Andrija [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.