PHP Regex preg_match showing unusual behavior

Question

Here is the pattern:

$urlpattern = '%[^http://][^https://][\w]+(-[\w]+)*(\.[\w]+(-[\w]+)*)*\.[\w]{1,6}(\.[\w]{1,6})*[^/]%';

I have encountered a strange bug that boggles me.

When I search against a string like 'power-tool-world.com' it gimps it and returns 'ower-tool-world.com' (removes the p) but when I use any other letter(not tested on EVERY other letter) it works fine, so 'cower-tool-world.com' returns 'cower-tool-world.com' can someone please help me understand why, but more importantly give me a solution that wouldn't cause this problem?

mck89 · Accepted Answer · 2011-09-09 10:25:48Z

2

The error is in the first part. When you use square brackets you match one of the characters inside them so [http://] matches h, t, p, : and /, and these characters will be excluded from the next matching group. You should use ^(http://|https://)? instead.

answered Sep 9, 2011 at 10:25

mck89

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4 Comments

Tim Pietzcker Over a year ago

Not quite. [^http://] matches any character except h, t, p, : or /. And of course ^(https?://)? would be the preferable alternative.

Serj Sagan Over a year ago

No, although you might be on the right track, your solution returns a false, saying that power-tool-world.com does not match

Serj Sagan Over a year ago

Your point makes sense because both h & t return the same thing but what is the correct solution?

mck89 Over a year ago

@Tim Pietzcker you are right but i've interpreted it as a typo because i thought that he was looking for a string that optionally starts with http:// or https://.

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