Hello- A basic question which has nonetheless floored me entirely. I have a dataset which looks like this:
Type ID Date Value A 1 16/09/2020 8 A 1 23/09/2010 9 B 3 18/8/2010 7 B 1 13/5/2010 6 There are two Types, which correspond to different individuals in different conditions, and loads of ID labels (1:50) corresponding to the different individuals in each condition, and measurements at different times (from 1 to 10 measurements) for each individual. I want to perform the following operations: 1) Delete all individuals for whom only one measurement is available. In the dataset above, you can see that I want to delete the row Type B ID 3, and Type B ID 1, but without deleting the Type A ID 1 data because there is more than one measurement for Type A ID 1 (but not for Type B ID1) 2) Produce difference scores for each of the Dates, so each individual (Type A ID1 and all the others for whom more than one measurement exists) starts at Date "1" and goes up in integers according to how many days have elapsed. I just know there's some incredibly cunning R-ish way of doing this but after many hours of fiddling I have had to admit defeat. I would be very grateful for any words of advice. Many thanks, Chris Beeley, Institute of Mental Health, UK ______________________________________________ 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.
