Create a counter variable

[desireatem]

I have this data set and I want to create a count variable for number of time in hospital;

Id            date                               

001         01/07/17 

001         03/07/17

002         01/07/17

003         02/01/17

003         04/05/17

004         05/05/17

;

I want to create a third variable number of visit such that the data becomes;

Id            date                number_visit                   

001         01/07/17                  1

001         03/07/17                  2

002         01/07/17                  1

003         02/01/17                  1

003         04/05/17                  2

004         05/05/17                  1

best.

[Reeza · Accepted solution]

See the solution here to create a counter variable:

http://stats.idre.ucla.edu/sas/faq/how-can-i-create-an-enumeration-variable-by-groups/

[Jagadishkatam]

alternatively, you could also try the proc sql monotonic()

proc sql;
create table want as select *, (monotonic()-min(monotonic())+1) as number_visit from have group by id;
quit;