Regular Expression for domain from email address

Question

Hi,

Can anyone help me with a regular expression that will return the end part of an email address, after the @ symbol? I'm new to regex, but want to learn how to use it rather than writing inefficient .Net string functions!

E.g. for an input of "[email protected]" I need an output of "example.com".

Cheers! Tim

Answer 1

@(.*)$

This will match with the @, then capture everything up until the end of input ($)

Answer 2

A simple regex for your input is:

^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$

But, it can be useless when you apply for a broad and heterogeneous domains.

An example is:

^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.(?:[A-Z]{2}|com|org|net|gov|mil|biz|info|mobi|name|aero|jobs|museum)$

But, you can optimize that suffix domains as you need.

But for your suffix needs, you need just:

@.+$

Resources: http://www.regular-expressions.info/email.html

Answer 3

A regular expression is quite heavy machinery for this purpose. Just split the string containing the email address at the @ character, and take the second half. (An email address is guaranteed to contain only one @ character.)

Answer 4

This is a general-purpose e-mail matcher:

[a-zA-Z][\w\.-]*[a-zA-Z0-9]@([a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z])

Note that it only captures the domain group; if you use the following, you can capture the part proceeding the @ also:

([a-zA-Z][\w\.-]*[a-zA-Z0-9])@([a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z])

I'm not sure if this meets RFC 2822, but I doubt it.