Date:         Fri, 16 Jul 2010 21:47:59 -0400
Reply-To:     SUBSCRIBE SAS-L Anonymous <hari.sas.j@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         SUBSCRIBE SAS-L Anonymous <hari.sas.j@GMAIL.COM>
Subject:      Counter

Hi,
I have a dataset with three variables, subject date flag. Basically I need
to index in such a away that as soon as the flag = 1 then index is set 0 and
any observation which has a lower value date is indexed -1, -2 and  so on ..
and any observation that has higher date value than the (flag = 1) is
indexed +1, +2 and so on within the group subject.Below is the program that
creates raw data and also the desired output is shown below as well

data alldata;

  input subject $ date $12. flag;
  datalines;
Subject1 5/1/2010 0
Subject1 6/1/2010 0
Subject1 7/1/2010 1
Subject1 8/1/2010 0
Subject1 9/1/2010 0
Subject1 10/1/2010 0
Subject2 1/1/2010 0
Subject2 2/1/2010 1
Subject2 3/1/2010 0
Subject2 4/1/2010 0
;
run;

data alldata1;
  set alldata (rename = (date = datem));

  date = input(datem,mmddyy10.);

  format date date9.;
run;

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Desired output:

subject  date        flag index
Subject1 5/1/2010 0 -2
Subject1 6/1/2010 0 -1
Subject1 7/1/2010 1 0
Subject1 8/1/2010 0 1
Subject1 9/1/2010 0 2
Subject1 10/1/2010 0 3
Subject2 1/1/2010 0 -1
Subject2 2/1/2010 1 0
Subject2 3/1/2010 0 1
Subject2 4/1/2010 0 2

Advanced thanks for help

Regards,

Hari