Hi, I have the following data: > data[1:20,c(1,2,20)] idr schyear year 1 8 0 1 9 1 1 10 NA 2 4 NA 2 5 -1 2 6 0 2 7 1 2 8 2 2 9 3 2 10 4 2 11 NA 2 12 6 3 4 NA 3 5 -2 3 6 -1 3 7 0 3 8 1 3 9 2 3 10 3 3 11 NA
What I want to do is replace the NAs in the year variable with the following: idr schyear year 1 8 0 1 9 1 1 10 2 2 4 -2 2 5 -1 2 6 0 2 7 1 2 8 2 2 9 3 2 10 4 2 11 5 2 12 6 3 4 -3 3 5 -2 3 6 -1 3 7 0 3 8 1 3 9 2 3 10 3 3 11 4 I have no idea how to do this. What it needs to do is make sure that for each subject (idr) that it either adds a 1 if it is preceded by a value in year or subtracts a 1 if it comes before a year value. Does that make sense? I could do this in Excel but I am at a loss for how to do this in R. Please reply to me as well as the list if you respond. Thanks! Chris [[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.