PHP Regex - negate a match if it contains a word (string)

Question

I've tried many ways to do this, the only one which seems to partially do what I want is the lookahead negation described in String negation using regular expressions and How to negate specific word in regex? but I can't get it to work with my current regex.

Assuming I have this string:

[url=http://www.example.com]this url BB tag should match[/url]
[url=http://www.example.com][spoiler]this url BB tag shouldn't match[/spoiler][/url]

Edit: More in-depth string which shouldn't return a match for debugging:

[url=http://www.example.com]Lorem[spoiler]this url BB tag shouldn't match[/spoiler]Ipsum[/url]

And the current regex pattern:

#\[url=([\w]+?://.*?)\]([^?\n\r\t].*?)\[/url\]#is

Edit: I'm using the following regex (without # and #is) to debug it on Regex Buddy:

\[url=([\w]+?://.*?)\]([^?\n\r\t].*?)\[/url\]

(these 2 regex should have the same effect on my application as I can easily adapt it, so work with the latter if it makes more sense)

Will match both lines in the string. I want it to don't return a match when there's a [spoiler] string between the [url=xxxx://yyyy] and [/url].

I think it can be done with the negative lookahead but I can't seem to find a way to insert it in the current regex without turning it unusable.

Any help is appreciated.

Rezigned · Accepted Answer · 2012-04-18 03:22:55Z

1

This should solve the problem.

'#\[url=([^\]]+)\](?!\[spoiler\])(.*?)\[/url\]#'

answered Apr 18, 2012 at 3:22

Rezigned

4,9501 gold badge22 silver badges19 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Fabrício Matté Over a year ago

It's still returning a match for [url=http://www.google.com][spoiler][/spoiler][/url] on my php and regex testers.

Rezigned Over a year ago

Here's my test

preg_match('#\[url=([^\]]+)\](?!\[spoiler\])(.*?)\[/url\]#', '[url=http://www.google.com][spoiler][/spoiler][/url]', $m); print_r($m);

It returns nothing tho (which is what you want).

Fabrício Matté Over a year ago

Oh sorry, for my comment above it actually doesn't return a match for your regex, however, if I add any character before the [spoiler] it'll return a match: [url=http://wwww.google.com]Hi[spoiler][/spoiler][/url]

Fabrício Matté Over a year ago

Adding a .* inside the lookahead seems to do the trick, I'll debug it and post results.

Fabrício Matté Over a year ago

Alright, (?!.*\[spoiler\]) lookahead does the trick, but I still wanted to keep the \w iteration and :// check for this pattern, so here's the final regex: #\[url=(?=[^_\W]+?://)([^\]]+)\](?!.*\[spoiler\])(.*?)\[/url\]#i. Thanks for the help.

|

Collectives™ on Stack Overflow

PHP Regex - negate a match if it contains a word (string)

1 Answer 1

6 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related