Re: st: numbering observations when variables change

[Nick Cox <n.j.cox@stata.com>]

What you wrote gives the number of observations for each combination of 
variables. You want

. egen id = group(name year)

Nick
n.j.cox@durham.ac.uk

Fabian Brenner wrote:

> I want to use variable "id" to number observations. Whenever "name" or "year" changes, "id" should increase by 1. I have sorted the data by name and year (-sort name year-). I tried to solve the problem by -bysort name year: generate id=_N- but it did not work.
>
> Hopefully someone can help me.
>
> Regards,
> Fabian
>
> Example:
> "id"       "name"    "year" 
> 1         A            1990
> 1         A            1990
> 2         A            2001
> 3         B            2001
> 4         B            2003
> 5         B            2007
> 5         B            2007       
> 6         C            2007
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