Using RegEx to match domain.com and www.domain.com but NO OTHER subdomains?

Question

Sorry if this has been asked elsewhere, I've been looking and can't find it for the life of me. I am attempting at tackling regular expressions, I've ALWAYS had problems with the more advanced scenarios... well, others find them quite easy, so maybe there's something wrong with me.

Anyway, I am attempting to write a RegEx that matches www.domain.com OR domain.com but NO OTHER SUBDOMAINS or anything. The only two strings I want to pass the regex are "domain.com" and "www.domain.com" and I haven't been able to find exactly what I am looking for other than including all subdomain matching, which I find easy.

The closest I have come is this: regex for matching something if it is not preceded by something else but in that case its failing only for one preceding string, I want it to succeed for only one preceding string/subdomain. Note, "domain.com" will always be static, meaning it will always be that exact string "domain.com" not various domains.

Thanks so much for shedding light on this!

Tyler

Please use `example.com` and friends for example domains. I doubt you own domain.com. — Quentin, Feb 20 '12 at 12:56

score 7 · Accepted Answer · answered Feb 20 '12 at 12:55

7

Just put the optional part in a non-capturing group, and make it optional.

/^(?:www\.)?example.com$/

answered Feb 20 '12 at 12:55

Quentin

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The same with a capturing group (without `?:`) would work too, but is probably slower. – jofel Feb 20 '12 at 12:58
Thanks, too simple for me to even see apparently. It works as expected. – Tyler Feb 21 '12 at 21:41

Using RegEx to match domain.com and www.domain.com but NO OTHER subdomains?

1 Answers1