Why is regex matching ":www.xxx.com"

Asked Aug 17 '18 at 08:53

Active Aug 17 '18 at 09:03

Viewed 1,076 times

I got the following code snipped from a popular website, for PHP regex validation.

I'm a novice and am playing around with regex. When I put a colon ":" in front of the URL, for $website as below (":www.xxx.com"), the expression still matches. I can't figure out why this should match. (for instance, $website = "zwww.xxx.com" doesn't match, which is expected). I tried regex 101, and thought the behavior might have something to do with the \b at the beginning of the regex, but even when I remove the \b, it still matches on ":www.xxx.com" or "&www.xxx.com", etc.) Many thanks for explaining!

    <?php
    $website = ":www.xxx.com";
    if (preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*
        [-a-z0-9+&@#\/%=~_|]/i",$website)) {
        echo "Matched!";
    } else {
        echo "Not Matched!";
    }
    ?>

edited Aug 17 '18 at 09:03

asked Aug 17 '18 at 08:53

Crowdpleasr

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There is a word boundary between `:` and `w`, that is why. – Wiktor Stribiżew Aug 17 '18 at 08:55
@Crowdpleasr Also, just in case you missed it: the fact that your regexp isn't surrounded by `^` and `$` means any part of the string can be matched by the regexp. Doesn't have to be the whole thing. – Jeto Aug 17 '18 at 08:57
OK, many thanks. I see now. – Crowdpleasr Aug 17 '18 at 09:06

Why is regex matching ":www.xxx.com"

0 Answers0