In addition to other answers, please note an FAQ on
the question:
How do I compute the number of distinct observations?
http://www.stata.com/support/faqs/data/distinct.html
Terminology is troubled here: as a small child
I was told that unique meant something that
occurred once only. But no matter:
. search unique
would have pointed you to the FAQ mentioned
above, which discusses general principles and a
clutch of user-written programs.
Nick
[email protected]
Scott Imberman
> I was wondering if there is s a simple way to count the number of
> unique values in a variable list for each observation. For example, i
> am looking at the id numbers for colleges that a set of
> student attends.
> A student may list having attended a college in multiple years like
> this:
>
> year id
>
> 1995 3
> 1996 2
> 1997 3
> 1998 3
>
> I want to know how many unique schools the student attended (in this
> example the answer is 2). Thanks for your help.
*
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