Python regexp to match e-mail against domain names

Question

I'm looking for the "perfect" regexp's to validate if an e-mail belongs to a domain name (including sub-domains), for example:

www.domain.com : [email protected]
sub.domain.com : [email protected]
domain2.com : [email protected]

Answer 1

Taken from django:

email_re = re.compile(
    r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z]+)*"  # dot-atom
    r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-011\013\014\016-\177])*"' # quoted-string
    r')@(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+[A-Z]{2,6}\.?$', re.IGNORECASE)  # domain