REGEX email matching

Question

I have a JAVA string that is being used to validate proper email addresses.

^[\\w'-]+(\\.[\\w'-]+)*@[A-Za-z0-9]+([.-][A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$

I want to user to be able to leave the address blank and not get an error message. How is this possible?

Just make a condition for that. Its easier than reconfiguring the whole regular expression. — Havenard, May 20 '13 at 19:24
What programming language are you using? There may be a better solution than regex. Email addresses aren't easy to parse using a regex, but many languages have fairly standard functions for validating email addresses. For example, in PHP, you can simply use `filter_var()`; no regex required. — Spudley, May 20 '13 at 19:30

score 0 · Accepted Answer · answered May 20 '13 at 19:25

0

Since you didn't provide any other code or specify what language you were using, the best I can suggest is:

(?:^[\\w'-]+(\\.[\\w'-]+)*@[A-Za-z0-9]+([.-][A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$)|(?:^$)

Which will match an e-mail or an empty string.

answered May 20 '13 at 19:25

qJake

2

This will only match email adresses not containing non-english characters – crackmigg May 20 '13 at 19:35
@migg This was the OP's regex, not mine. I just added the check for the empty string. – qJake May 20 '13 at 19:37
Sorry about that, new to the forum. Using Java – koddos May 20 '13 at 19:57

score 0 · Answer 2 · answered May 20 '13 at 19:26

0

If you have an expression you want to make optional allowing empty string to match you could use any of the following:

^(?:regex)?\z
^\z|^regex\z

answered May 20 '13 at 19:26

Qtax

2 Answers2