Hello, I have the following dataset (this is a piece of a much larger set):
RID SCRNO VISCODE RECNO CONTTIME 23 18 HBA0190012 bl 1 5 24 18 HBA0190012 bl 3 5 28 18 HBA0190012 bl 5 5 29 18 HBA0190012 bl 2 5 32 18 HBA0190012 bl 4 5 38 19 HBA0190013 bl 2 35 50 19 HBA0190013 bl 1 5 57 20 HBA0190014 bl 1 10 61 21 HBA0200015 bl 2 30 64 21 HBA0200015 bl 3 90 67 21 HBA0200015 bl 4 90 72 21 HBA0200015 bl 8 2 76 21 HBA0200015 bl 1 60 88 22 HBA0190016 bl 1 25 97 23 HBA0190017 bl 3 85 99 23 HBA0190017 bl 1 5 103 23 HBA0190017 bl 2 5 122 25 HBA0190019 bl 1 20 145 26 HBA0200020 bl 1 60 170 27 HBA0190021 bl 1 3 190 28 HBA0220022 bl 1 40 194 29 HBA0220023 bl 1 25 223 29 HBA0220023 bl 2 25 And I would like to output a list of the sums of CONTTIME for each SCRNO. What is the best way to do that? Any help would be greatly appreciated. Thanks! Edgar ______________________________________________ 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.