Date:         Wed, 18 Apr 2007 19:50:34 -0700
Reply-To:     proc sas <sumanta24@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         proc sas <sumanta24@GMAIL.COM>
Organization: http://groups.google.com
Subject:      Help in creating new variable
Comments: To: sas-l@uga.edu
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Hi All,

I have a dataset like this:

app_num mon     yr      age
111     1       2004    0
111     2       2004    1
111     3               .
111     12      2004    11
111     1       2005    12
111                     .
111                     40
222     5       2004    0
222     6       2004    1
222                     .
222                     .
222                     40

Now i need to calculate variable mm and tyr such that,

when mon=1 and yr=2004 and age=0 then mm=1 and tyr=2004
when mon=1 and yr=2004 and age=1 then mm=2 and tyr=2004
...............
when mon=1 and yr=2004 and age=11 then mm=12 and tyr=2004
when mon=1 and yr=2005 and age=12 then mm=1 and tyr=2005

I have this data for several app_num, whose starting point may vary,
like for app_num=111,
mon=1 and year=2004

for app_num=222,
mon=5 and year=2005.
For app_num the condition will be,
when mon=5 and yr=2005 and age=0 then mm=5 and tyr=2005
when mon=5 and yr=2005 and age=1 then mm=6 and tyr=2005
.............
when mon=5 and yr=2005 and age=7 then mm=12 and tyr=2005
when mon=5 and yr=2005 and age=8 then mm=1 and tyr=2006

How simply i can develop this logic? f i'm unable to make you
understand please feel free to ask me questions.

Thanks.