See
http://www.stata-journal.com/abstracts/pr0004.pdf
and you may eventually want
http://www.stata.com/support/faqs/data/distinct.html
or
http://www.stata.com/support/faqs/data/anyall.html
or
http://www.stata.com/support/faqs/data/members.html
as well.
On Sun, Sep 27, 2009 at 8:17 AM, Thomas Cars <[email protected]> wrote:
> Hi,
> I have a dataset including subjects (id) and date for administration of a
> specific drug (adm.date)
>
> I now want to construct a variable telling me which one of the observations
> (adm.date) in each subject (id) that has the lowest date (min) and the
> highest date(max).
>
> The number of adm.date can vary in each subject from 1 to 10.
>
>
> Example (min=1 och max=2)
>
>
>
> Id adm.date min/max
>
> 1 12may06 1
> 1 20jun06
> 1 30aug06 2
> 2 10may06 1
> 2 10sep06
> 2 20dec06
> 2 10jan07 2
> 3 10aug06 1
> 3 20sep06
> 3 10dec06
> 3 15jan07
> 3 10feb07 2
>
> And so on?
>
> I hope anyone can help me!
>
> Thomas
>
>
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