SAS Code help!

[buszhangsy]

Hi PG, I examined the data on 20 patients and the code does its job!

Thanks a lot!

[Ksharp]

If I understood what you mean.

data have;
input Patient_ID   $         Medication_name  $     Service_date : mmddyy10.;
format      Service_date  mmddyy10.;
cards;
0000120              QVar                           08/07/2007
0000120              SPIRIVA                     08/14/2007
0000120              SPIRIVA                     11/14/2007
0000120              SPIRIVA                     01/16/2008
0000120              QVar                           12/05/2008
0000120              SPIRIVA2                     08/13/2007
0000120              SPIRIVA2                     11/13/2007
0000120              SPIRIVA2                     01/15/2008
0000120              SPIRIVA3                     08/15/2007
0000120              SPIRIVA3                     11/15/2007
0000120              SPIRIVA3                     01/17/2008
0000120              SPIRIVA4                     01/11/2008
;
run;
data temp;
 if _n_ eq 1 then do;
  if 0 then set have;
  length rank 8;
  declare hash ha();
   ha.definekey('Medication_name');
   ha.definedata('rank');
   ha.definedone();
 end;
set have;
by      Patient_ID;
if ha.find() ne 0 then do;r+1;rank=r;ha.add();end;
if last.Patient_ID then do;ha.clear(); r=0;end;
drop r;
run;


proc sort data=temp ; by Patient_ID rank Service_date;run;

data x;
 set temp;
 by Patient_ID rank;
 if first.rank then n=0;
 n+1;
 lag_Service_date= lag(Service_date) ;
 month=intck('month',lag_Service_date,Service_date,'c');
 if n=2 and month le 6;
 keep  Patient_ID Medication_name lag_Service_date;
 format lag_Service_date mmddyy10.;
run;

data want;
 set x;
 by Patient_ID;
 if first.Patient_ID;
run;

Xia Keshan

Message was edited by: xia keshan