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Re: st: Keeping and dropping data


From   "Dev Vencappa" <[email protected]>
To   <[email protected]>
Subject   Re: st: Keeping and dropping data
Date   Fri, 16 Dec 2005 11:37:50 +0000

>
Kevin, 
if I understood clearly what you want to do, the following may do that:

gen Z=minyear
gen Y=maxyear
forvalues x=1/5{
sum lboyear
replace Z=r(min) if regno==`x'
replace Y=r(max) if regno==`x'
}
keep regno lboyear exityear X if lboyear==Z|Zlboyear==Y|lboyear==.

Hope that does what you want.

Dev

>>> [email protected] 12/16/05 11:04 am >>>
Dear all 

I've got mysefl stuck on this little problem. My data is in the following form:

regno   lboyear exityear  X....
1            1992     2003
1            2000        .
1            1992     1996
1            1996     2000
2            2000     2003
2            1993     2000
3            1997        .
3            1993     1997
4            2000        .
5            1999     2002

I would like to:
1. Keep the earliest lboyear and the X variables associated with this earliest lboyear
2. Keep the latest exit year. Note that . indicates no exit, so I would want to keep the dot and not the latest year. I think this is handy as Stata stores it as +infinity.

Any advice is much appreciated.

Kevin


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