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
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