Regular expression negation

How to negate a phrase in regex?

[frex65]

Hi all,
I'm trying to negate a phrase rather than just a single character in a regular expression. Is there a syntax for multiple character negation? For example, if 'Brenda Brown' and 'Brenda Jones' are OK, but not 'Brenda Smith'?
Regex is such a powerful tool -surely there's a multiple negation operator.
Thanks - much appreciated,
Frex

[coopster]

Welcome to WebmasterWorld, frex65!

Well, there are a few ways to accomplish your goal, but a zero-width, negative lookahead assertion [php.net] is the tool you will more than likely end up using. A lookahead assertion is a test on the characters following the current matching point that does not actually consume any characters. And in this case, it is a negative assertion or, "don't match this":

$string = "'Brenda Brown' and 'Brenda Jones' are OK, but not 'Brenda Smith'?"; 
 // There's a space after Brenda in the next line: 
preg_match_all("/'Brenda (?!Smith').*'/Uis", $string, $matches); 
print "$string<br />"; 
print "<pre>"; print_r($matches); print "</pre>"; 

Will give you this:

'Brenda Brown' and 'Brenda Jones' are OK, but not 'Brenda Smith'? 
Array 
( 
  [0] => Array 
    ( 
      [0] => 'Brenda Brown' 
      [1] => 'Brenda Jones' 
    ) 
) 

[frex65]

Cheers coopster, especially for that link to info on assertions. It works beautifully. Very much appreciated.