Date:         Fri, 10 Jan 2003 10:04:45 -0800
Reply-To:     D McGooey <darlene_mcgooey@HOTMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         D McGooey <darlene_mcgooey@HOTMAIL.COM>
Organization: http://groups.google.com/
Subject:      can I use the lag function to do this?
Content-Type: text/plain; charset=ISO-8859-1

I was reading some recent posts about the lag function, and I am
confused.  This is, conceptually what I want to try to do:

I have three variables: a(i...n), b(i...n) and c(i...n).  For record
1, a=b=c.
For the remaning records: a[i]=a[i], b[i]=a[i]*b[i-1],
c[i]=a[i-1]*b[i-1]*c[i].
The problem is how do I access one element past for calculating the
value  b[i] and c[i].  I think the lag function could work, but the
sas code is not working with me.  There is very little documentation
that I can find to explain it.  Is this even possible in sas (well of
course it is, but is it possible for ME in sas)?

DM