RE: st: Keeping specific observations

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

egen n = count(v1), by(id)
keep if n>0

HTH,

- Elan


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Eleimon Gonis
Sent: Friday, August 31, 2012 12:56
To: statalist@hsphsun2.harvard.edu
Subject: RE: st: Keeping specific observations

Hi Afif,

thanks for your reply, but no, it wouldn't work, because that command would also drop the second individual's missing value in 2001, which I want to keep. 
What I'm trying to get is that if an individual has at least one non-missing value in any of the years (ID=1 and 2 in the example), they should remain, otherwise drop.

Eleimon

From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] On Behalf Of Afif Naeem [afeef745@hotmail.com]
Sent: 31 August 2012 17:46
To: statalist@hsphsun2.harvard.edu
Subject: RE: st: Keeping specific observations

Shouldnt "drop if v1 == . " work?

Afif

> From: Eleimon2.Gonis@uwe.ac.uk
> To: statalist@hsphsun2.harvard.edu
> Date: Fri, 31 Aug 2012 17:43:47 +0100
> Subject: st: Keeping specific observations
>
> Dear Statalisters,
>
> I would appreciate your help with the following conundrum. Assume I have a dataset that looks like this:
>
> Year         ID        v1
> 2000         1          2
> 2001         1          2
> 2002         1          3
> 2000         2          3
> 2001         2          .
> 2002         2          3
> 2000         3          .
> 2001         3          .
> 2002         3          .
>
> What I want to achieve is to only keep those individuals that appear with any non-missing values for v1 for any of the years in the dataset.
>
> In other words, I don't think that a command: "keep if v1<." would do, because that would also take out the 2001 observation for the second individual (ID==2), which I'd like to remain in place.
>
> Any ideas are welcome,
> Eleimon
>
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