st: RE: Dropping all subjects but those in the last period

["Cohen, Elan" <cohened@upmc.edu>]

Let's assume 2010 is the "last year".  Then:

egen flag = total(year==2010), by(id)
drop if !flag

HTH,

- Elan


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Miguel Angel Duran
Sent: Monday, April 08, 2013 15:27
To: statalist@hsphsun2.harvard.edu
Subject: st: Dropping all subjects but those in the last period

My dataset includes observations for about 9000 companies per year in a
twenty years period. To clean the dataset, I would like to drop all those
companies that are not present in the last year (because the rest went
bankrupt or were absorbed), but I do not know how to do it. Can this be done
just by splitting the datasets by period and then merging them?  Each
company has the same id across years. Thanks.

Miguel A. Duran.

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