regular expression for validating url with sub-domain
问题 preg_match('/^(http:\\/\/)?(.+)\.MYDOMAIN\.com(.*)/', $url, $match) This is my regex to validate a URL that must have a sub-domain, but if someone uses www instead of sub-domain it also gets validated. For example: http://shoes.en.MYDOMAIN.com/ This must pass http://www.MYDOMAIN.com/ This must fail How can I edit my regex to fail if the sub-domain is www ? 回答1: I think you can do it with a negative lookahead assertion: (?!www\.) which being placed after the protocol check, checks if there is