Dear Statalist,
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.
Sincerely,
Scott Imberman
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Scott Andrew Imberman
Department of Economics
3105 Tydings Hall, University of Maryland
College Park, MD 20742
Voice: (301) 405-4534
Fax: (301) 405-3542
[email protected]
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