Extract domain name from a host name

Question

Is there a programatic way to find the domain name from a given hostname?

given -> www.yahoo.co.jp return -> yahoo.co.jp

The approach that works but is very slo

Answer 1

You can use partition instead of split:

>>> 'www.yahoo.co.jp'.partition('.')[2]
'yahoo.co.jp'

This will help with the parsing but obviously won't check if the returned string is a valid domain.