add group id

[SAS42]

Hi,

I have dataset as follows:

Group Value

a          1

a          2

a          3

b          1

b          2

b          3

....

Is there a way to add group id to the dataset like follows:

Group Value  group_id

a          1         1

a          2         1

a          3         1

b          1         2

b          2         2

b          3         2

....

I can use proc sql and join to do this, but is there any other simpler way?

[ballardw · Accepted solution]

Assuming the data is sorted by group

data want;
   set have;
   by group;
   retain group_id 0;
   if first.group then group_id+1;
run;

If the data is grouped by the group variable but not in sort order:

data want;
   set have;
   by  group notsorted;
   retain group_id 0;
   if first.group then group_id+1;
run;

[SAS42]

Thank you very much. It worked.