PHP preg_match_all RegEx conflict - php

Question

if (preg_match_all ("/\[protected\]\s*(((?!\[protected\]|\[/protected\]).)+)\s*\[/protected\]/g", $text, $matches)) {
var_dump($matches);
var_dump($text);
}
The text is
<p>SDGDSFGDFGdsgdfog<br>
[protected]<br> STUFFFFFF<br>
[/protected]<br> SDGDSFGDFGdsgdfog</p>
But $matches when var_dump ed (outside the if statement), it gives out NULL
Help people!

Answer 1

You're using / (slash) as the regex delimiter, but you also have unescaped slashes in the regex. Either escape them or (preferably) use a different delimiter.
There's no g modifier in PHP regexes. If you want a global match, you use preg_match_all(); otherwise you use preg_match().
...but there is an s modifier, and you should be using it. That's what enables . to match newlines.
After changing your regex to this:
'~\[protected\]\s*((?:(?!\[/?protected\]).)+?)\s*\[/protected\]~s'
...I get this output:
array(2) {
[0]=>
array(1) {
[0]=>
string(42) "[protected]<br> STUFFFFFF<br>
[/protected]"
}
[1]=>
array(1) {
[0]=>
string(18) "<br> STUFFFFFF<br>"
}
}
string(93) "<p>SDGDSFGDFGdsgdfog<br>
[protected]<br> STUFFFFFF<br>
[/protected]<br> SDGDSFGDFGdsgdfog</p>"
Additional changes:
I switched to using single-quotes around the regex; double-quotes are subject to $variable interpolation and {embedded code} evaluation.
I shortened the lookahead expression by using an optional slash (/?).
I switched to using a reluctant plus (+?) so the whitespace following the closing tag doesn't get included in the capture group.
I changed the innermost group from capturing to non-capturing; it was only saving the last character in the matched text, which seems pointless.

Answer 2

$text= '<p>SDGDSFGDFGdsgdfog<br>
[protected]<br> STUFFFFFF<br>
[/protected]<br> SDGDSFGDFGdsgdfog</p>';
if (preg_match_all ("/\[protected\]\s*(((?!\[protected\]|\[\/protected\]).)+)\s*\[\/protected\]/x", $text, $matches)) {
var_dump($matches);
var_dump($text);
}
There is no g modifier in preg_match - you can read more at Pattern Modifiers . Using x modifier works fine thou.