By "unique" here I think you mean "distinct".
Try -groups- from SSC. Or -egen, group()-
and then tabulate.
Nick
[email protected]
Wanli Zhao
> I have a simple question but got stuck on a simple solution.
> I have a panel
> and let's say cross-section id is gvkey and time id is year.
> There are two
> variables, say, primary sic and secondary sic. My aim to
> count the unique
> value of sic in both variables by gvkey by year. I know the
> 'by' thing is
> straightforward but is there a quick solution to count the unique
> observation in both variables? I know the commands such as
> unique, distinct
> and egenmore nvals. They work perfect for a single variable.
> Also, on the
> webpage there is a explanation of the unique combination of
> two variables and how to count that. I guess mine is different. Your help
> is appreciated.
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