Date:         Mon, 25 Sep 2006 11:30:21 -0400
Reply-To:     "Dorfman, Paul" <paul_dorfman@MERCK.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Dorfman, Paul" <paul_dorfman@MERCK.COM>
Subject:      Re: numbering observations
Comments: To: Arjen <a.benedictus@GMAIL.COM>
In-Reply-To:  <1159195282.766620.4520@i42g2000cwa.googlegroups.com>
Content-Type: text/plain; charset=us-ascii

Arjen,

A simple way is, as already indicated,

data a_need ;
   set a ;
   if a ne . then b = 1 ;
   else b ++ 1 ;
run ;

An alternative way based on the DoW logic (loop until stop-event) could
be:

data a_need ;
   do b = 1 by 1 until (a ne .) ;
      output ;
      set a ;
   end ;
run ;

But this produces an extra first observation. Of course, subsequently

set a_need (firstobs=2)

could be used, but it is a classic kludge. Try finding a kludge-free way
of eliminating the extra observation in the dow-step itself. Then
reflect on the fact that if SET and OUTPUT followed the "normal" order,
the extra record would be gone, but then the numbering would be off by
1. Think of the most aesthetic way to correct that (within the same
step, of course). It can be a useful exercise leading to a deeper
understanding how the DATA step works. Actually, this is the only reason
I offer this - as a puzzle rather than a solution.

Kind regards
------------
Paul Dorfman
Jax, FL
------------


+-----Original Message-----
+From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On
+Behalf Of Arjen
+Sent: Monday, September 25, 2006 10:41 AM
+To: SAS-L@LISTSERV.UGA.EDU
+Subject: numbering observations
+
+
+Hello all,
+
+I have dataset A:
+
+data A;
+input A;
+cards;
+1
+.
+.
+2
+.
+.
+1
+.
+.
+.
+;
+run;
+
+I would like to obtain dataset A_need:
+
+data A_need;
+input A B;
+cards;
+1 1
+. 2
+. 3
+2 1
+. 2
+. 3
+1 1
+. 2
+. 3
+. 4
+;
+run;
+
+As you can see, I want to number the observations "within" a given A.
+The point is that I cannot sort the table because the data is arranged
+in a peculiar way. As a result, the following code:
+data A_need;
+set A;
+by A;
+if first.A then B=1;
+else B+1;
+run;
+
+does not work as it requires sorting by A. In my dataset are several
+other variables, all character. I would appreciate your help. Thanks.
+
+Arjen
+
+


------------------------------------------------------------------------------
Notice:  This e-mail message, together with any attachments, contains
information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station,
New Jersey, USA 08889), and/or its affiliates (which may be known
outside the United States as Merck Frosst, Merck Sharp & Dohme or MSD
and in Japan, as Banyu - direct contact information for affiliates is
available at http://www.merck.com/contact/contacts.html) that may be
confidential, proprietary copyrighted and/or legally privileged. It is
intended solely for the use of the individual or entity named on this
message. If you are not the intended recipient, and have received this
message in error, please notify us immediately by reply e-mail and then
delete it from your system.

------------------------------------------------------------------------------