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From | Maarten Buis <maartenlbuis@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: Selecting within a subset of observations |
Date | Thu, 13 Jun 2013 11:16:59 +0200 |
On Thu, Jun 13, 2013 at 10:52 AM, Ada Keding wrote: > I am trying to use min/max or similar within a subset of observations. > > For example, I have one or more event dates for different identifiers: <snip> > Now I would like to create a variable that displays the latest event > date within each identifier. Here is how I would do this: *------------------ begin example ------------------ // copy your example dataset clear input ID str10 EventDate 1 "01/03/2011" 2 "31/01/2011" 2 "05/09/2011" 3 "12/03/2011" end // transform the datestring to Stata dates gen date = date(EventDate,"DMY") format date %td // find the most recent event per ID bys ID : egen last = max(date) // format it, so it also looks like a date format last %td // admire the results list *------------------- end example ------------------- * (For more on examples I sent to the Statalist see: * http://www.maartenbuis.nl/example_faq ) Hope this helps, Maarten --------------------------------- Maarten L. Buis WZB Reichpietschufer 50 10785 Berlin Germany http://www.maartenbuis.nl --------------------------------- * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/