Help with Grouping with multiple conditions

[NeehaP]

Hi Everyone,

Can anybody help in deriving the below "New" variable. For each patient, first group of flags should be 1, 2nd group of flags should be 2 and so on.

Pat	FL	New
1	y	1
1
1	y	2
1	y	2
1
1	y	3
1	y	3
1	y	3
2
2	y	1
2
2	y	2

[ballardw]

Keeping sequential values of a counter:

data want;
   set have;
   by notsorted pat fl;
   retain count ;
   if first.pat then count=.;
   if first.fl and fl='y' then count+1;
   if fl='y' then New=count;
   drop count;
run;

IF your data does not have all of the PAT values together you won't like the result.

At which point, good luck sorting your data to correct order unless there are a lot of other variables involved to manage such.

You may want to consider setting numeric flag values of 1 instead of character 'y'.

If you most common use is "if variable ='y' then <do something> you can simplify code to : if variable then <do>. SAS treats 1 as "true" in comparisons. To get number of "yes" you can just sum the flag values in any number of procedures which may be easier then counting 'y'.