Regex to detect one of several strings

I've got a list of email addresses belonging to several domains. I'd like a regex that will match addresses belonging to three specific domains (for this example: foo, bar, & baz)

So these would match:

1. a@foo
2. a@bar
3. b@baz

This would not:

1. a@fnord

Ideally, these would not match either (though it's not critical for this particular problem):

1. a@foobar
2. b@foofoo

Abstracting the problem a bit: I want to match a string that contains at least one of a given list of substrings.

Use the pipe symbol to indicate "or":

/a@(foo|bar|baz)\b/

If you don't want the capture-group, use the non-capturing grouping symbol:

/a@(?:foo|bar|baz)\b/

(Of course I'm assuming "a" is OK for the front of the email address! You should replace that with a suitable regex.)

^(a|b)@(foo|bar|baz)$

if you have this strongly defined a list. The start and end character will only search for those three strings.

Use:

/@(foo|bar|baz)\.?$/i

Note the differences from other answers:

• \.? - matching 0 or 1 dots, in case the domains in the e-mail address are "fully qualified"
• $ - to indicate that the string must end with this sequence,
• /i - to make the test case insensitive.

Note, this assumes that each e-mail address is on a line on its own.

If the string being matched could be anywhere in the string, then drop the $, and replace it with \s+ (which matches one or more white space characters)

should be more generic, the a shouldn't count, although the @ should.

/@(foo|bar|baz)(?:\W|$)/

Here is a good reference on regex.

edit: change ending to allow end of pattern or word break. now assuming foo/bar/baz are full domain names.