For a solution with the same dataset:
egen tag = tag(State County)
egen freq = total(tag), by(State)
egen tag2 = tag(State)
l State freq if tag2
See also for a discussion of principles
SJ-8-4 dm0042 . . . . . . . . . . . . Speaking Stata: Distinct observations
(help distinct if installed) . . . . . . N. J. Cox and G. M. Longton
Q4/08 SJ 8(4):557--568
shows how to answer questions about distinct observations
from first principles; provides a convenience command
Nick
On Fri, Jul 22, 2011 at 1:59 PM, Ben Hoen <bhoen@lbl.gov> wrote:
> Can someone help me to produce a table that counts the number of unique
> occurrences of a group inside another group?
>
> For example assume I had the following table:
>
> Number State County
> 1 NY Madison
> 2 NY Madison
> 3 PA Somerset
> 4 NY Oneida
> 5 PA Somerset
> 6 PA Wayne
> 7 PA Luzerne
>
> I want to produce a table like this:
> State County
> NY 2
> PA 3
>
*
* 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/
