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Re: st: First visit to clinic
From
Neil Shephard <[email protected]>
To
[email protected]
Subject
Re: st: First visit to clinic
Date
Mon, 20 Sep 2010 13:28:36 +0000
On Mon, Sep 20, 2010 at 1:24 PM, Paul O'Brien <[email protected]> wrote:
> i want to create a new variable with the date of the first visit of each patient:
>
> id date date_of_first_visit
> N-00-3558 07/04/2008 07/04/2008
> N-00-3558 09/04/2008 07/04/2008
> N-00-3558 14/05/2008 07/04/2008
> N-00-3563 05/06/2007
> N-00-3563 31/03/2010
> N-00-3565 05/06/2007
> N-00-3565 13/06/2008
> N-00-3565 13/06/2008
> N-00-3565 05/05/2009
> N-00-3565 04/03/2010
> N-00-3583 09/09/2008
> N-00-3583 27/05/2009
>
> i know this should be easy by i am having trouble using n_1
>
> i have tried:
> .sort date
> .by id, sort: gen visit=_n==1
>
> but the latter does not have the date in order, only id.
bysort id (date) gen date_of_first_visit = date[1]
should do the trick.
Neil
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