On 8 Mrz., 09:38, "rretzbach" <rretzb... / googlemail.com> wrote:
>       Indexes::Countries.countries.keys.find{|code| a[code] ==
> identifier}

Sry, too fast too furious!
a should be the same hash:

Indexes::Countries.countries.keys.find{|code|
Indexes::Countries.countries[code] == identifier}

Feel free to improve it :)