Date:         Tue, 16 Mar 2004 11:55:55 -0800
Reply-To:     Kristie K <kristie1273@YAHOO.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Kristie K <kristie1273@YAHOO.COM>
Subject:      looking ahead question
Content-Type: text/plain; charset=us-ascii

Hi SAS-L,
I have read through the archives the various ways of looking ahead in a dataset and am currently employing the

proc sort descending by variable of interest;
and then
data step to lag that variable

in order to get not only looking ahead for the variable of interest but also other information I need from that line of data.

here is my actual code;


proc sort data=selfrpt out=du (keep=invno ptno visitno vday visitdt dayuse dayusec op); by patid visitno descending op; run;

data du (drop=prevop);

set du;

by patid visitno;



prevop=lag(opiates);

if first.patid then prevop=.;

if op=1 and prevop=3 then op=4;

if last.visitno;

run;

I was wondering if it was possible to use a different method to look forward in the dataset using a type of merge firstobs=2 even though patid is multiple lines of the same data and visitno is unique?  And I would need these variables in the new dataset?  I read about 4 methods of looking forward in the data but was hoping for some assistance on the merge firstobs=2 method.

Thanks in advance,

Kristie



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