question on "Finding the First or Last Observation in a Group"

[helensh]

I follow the steps provided in the following website http://support.sas.com/documentation/cdl/en/basess/58133/HTML/default/viewer.htm#a001349233.htm.

proc sort data=Gta2 Out=Gta3;
   by Agmtcd;
run;

data sub_Gta3;
set Gta3;
by Agmtcd;
run;

data sub_Gta3;
set Gta3;
FirstAgmtcd=first.Agmtcd;
LastAgmtcd=last.Agmtcd;
run;

However, SAS says the variables "first.Agmtcd" and "last.Agmtcd" are not initialized. The format of Agmtcd is $10. Does anybody know what's wrong with my code?

Thanks a lot!

[art297 · Accepted solution]

You have 3 datasteps when you should only have 2.  The first. and last. variables are only available when a by statement is present within the SAME datastep.  Thus, try it with:

proc sort data=Gta2 Out=Gta3;
   by Agmtcd;
run;

data sub_Gta3;
  set Gta3;
  by Agmtcd;FirstAgmtcd=first.Agmtcd;

  LastAgmtcd=last.Agmtcd;
run;

[helensh]

It works. Thanks a lot!!!