How to make a regular program to get a domain zone?

Question

Regular Expressions

There is a list of domains and subdomains of this kind:

site.ru
lalal.sasa.com
and so on

Tell me how to make a regular expression so that it pulls out the domain zone after the last dot in the line?

Answer 1

/([^.]+)$/

Answer 2

(?<=\.)\w+(?=\.?$)
This regular expression "matches" alphanumeric characters located after the dot, and either before the end of the line, or before the dot with the end of the line after it.