I don't see how an index ordered by the magnitude of the value of a within each group b would help you randomly select one item per group. Why make it a composite index problem?

Try: proc sql; create table sampl as select distinct b,a,ranuni(111) as indx from test group by b having calculated indx=max(calculated indx) ; quit;

This selects at random a pair b,a for each unique value of b. Sig

-----Original Message----- From: yorgiv@MY-DEJA.COM at Internet-E-Mail Sent: Monday, July 10, 2000 8:48 PM To: SAS-L@LISTSERV.UGA.EDU at Internet-E-Mail Subject: index variable by group

Hello friends,

I would like to find a way to create an index variable in a single data set by a group. An example will help of course:

A B 5 1 3 2 12 2 8 1 1 2 2 1

then i do this:

proc sort; by B A; run; Now what I want is this:

B A index 1 2 1 1 5 2 1 8 3 2 1 1 2 3 2 2 12 3

I want to do this so that I can then use the ranuni function to randomly select an A from each group of B. But I have trouble creating the index variable as above. Thank you for any help,

Sincerely, Yorgi V.

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