By adding some Hash to Xia Keshan's code should fit your bill: data have;      input Application_id   Reaon_code   : $20.   Value $;      cards; 123 AB31AB45AB45 £500 124 AB43RD49TY87 £640 125 RT87RT87 £900 126 CD19RV29CD19 £1000 ; run; data want;      set have;      do i=1 to length(Reaon_code) by 4;            if i=1 then                 do;                      declare hash h1(ordered:'a');                      h1.definekey('i');                      h1.definedata('code','waterfall_reason');                      h1.definedone();                      declare hash h2();                      h2.definekey('code');                      h2.definedone();                      declare hiter hi('h1');                 end;            Waterfall_reason=ifn(i=1,1,0);            code=substr(Reaon_code,i,4);            if h2.check() ne 0 then                 do;                      rc=h2.replace();                      rc=h1.replace();                 end;      end;      unique_reason=ifn(h1.num_items=1,1,0);      do rc=hi.first() by 0 while (rc=0);            output;            rc=hi.next();      end;      drop i rc; run; ... View more