Date:         Thu, 13 Jul 2000 17:16:25 -0700
Reply-To:     Cassell.David@EPAMAIL.EPA.GOV
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "David L. Cassell" <Cassell.David@EPAMAIL.EPA.GOV>
Subject:      Re: Summarizing and choosing most populous ...
Comments: To: DN7423@momail.sbc.com
Content-type: text/plain; charset=us-ascii

David, you wrote:
> I need to:
>
>  1.) Sum all rev for each id (the easy part).
>  2.) Identify the most populous value of wc for each id.
>  3.) Identify the most populous value of sic for each id.
>  4.) Output one obs per id value.

You tried this with a DATA step.  I'm sure that you'll see DATA step
solutions and PROC SQL solutions, but there is a canned PROC which
will do all this for you.  PROC MEANS has a couple little-known options
in its output statement: MAXID and MINID .  PROC SUMMARY will do
this too.  I'll use the CLASS statement in my example so you can see that
it can handle a dataset your size even if the input is unsorted.  Given your
DATA step:

proc summary data=a;
  var rev;
  class id;
  output out=out1 sum=sumrev
         maxid( rev(wc) rev(sic) ) = bigwc bigsic;
  run;

proc print noobs data=out1;
  var id sumrev bigwc bigsic;
  run;

That's all there is to it.  Using a BY statement instead of a CLASS statement
when the data are sorted on the by-variable will let you do this with a much
larger
number of distinct by-variables, since then SAS won't have to hold everything
in memory.

David
--
David Cassell, OAO Corp.                           Cassell.David@epa.gov
Senior computing specialist
mathematical statistician