Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down at the end of May, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: st: First visit to clinic


From   "Martin Weiss" <martin.weiss1@gmx.de>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: First visit to clinic
Date   Mon, 20 Sep 2010 18:09:25 +0200

<>

Careful, though, Neil`s command seems to be lacking a colon after 

- bysort id (date)-...


HTH
Martin


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Neil Shephard
Sent: Montag, 20. September 2010 15:29
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: First visit to clinic

On Mon, Sep 20, 2010 at 1:24 PM, Paul O'Brien <paul.obrien@afe2.org.uk>
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

-- 
"One should as a rule, respect public opinion in so far as is
necessary to avoid starvation and to keep out of prison, but anything
that goes beyond this is voluntary submission to an unnecessary
tyranny, and is likely to interfere with happiness in all kinds of
ways..." - Bertrand Russell

Email - nshephard@gmail.com
Website - http://slack.ser.man.ac.uk/
Photos - http://www.flickr.com/photos/slackline/

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/


*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index