Hi, I have the following data: 0 12 1 10 1 4 1 6 1 7 1 13 2 21 2 23 2 20 3 18 3 17 3 16 3 27 3 33 4 11 4 8 4 19 4 16 4 9
In this data file I would like to sum the numbers of second column which belong to the same number in the first column. So the output would be: 0 12 1 40 2 64 3 111 etc. Thank you. Kind regards, T. Bal [[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.