data allergies2;
   length ID $ 5 LName FName $ 11 Plan $ 1 Blood $ 3 Allergy $ 1
          AlgyType $10;
   infile 'allergy.dat';
   input ID $ LName $ FName $ Plan $ Blood $ Allergy $ @;
   if Allergy='Y'; /*subsetting IF*/
      input AlgyType $ Dependents;
run;

proc print data=allergies2;
   title 'Patients with Allergies Only';
run;