reset counter to zero

[jenim514]

Hi!  I'm trying to count visits with the same date and then reset count to zero when encountering new subject.

This does what I need it to do, but how can I reset to ) when encountering new subject?

proc sort data= lb4; by usubjid lbdat visitx ; run;

data want;

set have;

by subject  lbdat;

if first.lbdat then vscount +1;

run;

Thanks!

[novinosrin]

Try

proc sort data= lb4; by usubjid lbdat visitx ; run;

data want;

set have;

by subject  lbdat;

if first.subject then vscount=1;

else if first.lbdat then vscount +1;

run;

[Tom]

Use the FIRST.USUBJID variable, just like you are using the FIRST.LBDAT variable.

proc sort data= lb4;
  by usubjid lbdat visitx ; 
run;

data want;
  set lb4;
  by usubjid lbdat;
  if first.usubjid then vscount=0;
  vscount + first.lbdat;
run;