Hello. I have a patient dataset with observations by participant. I want to flag participants with multiple observations in the dataset. See below for an example.
FID | Flag (want) |
1 | 1 |
1 | 0 |
2 | 0 |
3 | 0 |
4 | 1 |
4 | 0 |
4 | 0 |
5 | 0 |
data want;
set have;
by fid;
flag = (first.fid and not last.fid);
run;
Thanks @Kurt_Bremser. It seems that your code flagged the first observation for every participant. Is there a way to change the code so that it only flags those with multiple observations. If a participant has only one observation I dont want them flagged.
Simply cannot be with the data you posted and my code:
data have;
input fid;
datalines;
1
1
2
3
4
4
4
5
;
data want;
set have;
by fid;
flag = (first.fid and not last.fid);
run;
proc print data=want noobs;
run;
Result:
id flag 1 1 1 0 2 0 3 0 4 1 4 0 4 0 5 0
Matches exactly with your expected result from your initial post:
FID Flag (want) 1 1 1 0 2 0 3 0 4 1 4 0 4 0 5 0
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