Question

Possible Duplicate:
Regular expression: match all words except

I need your help for using Regex in PHP to negate a selection. So I have a string like this :
“Hello my name is tom”

What I need to do is to delete everything from this string witch is not “tom” or “jack” or “alex” so I tried :

$MyString = "Hello my name is tom"
print_r(preg_replace('#^tom|^jack|^alex#i', '', $MyString));

But it’s not working…

Can you help me with that ?
Thanks

Answer 1

If you want to delete everything except something, may be it’s better done the other way around: capture the something only? For example…

$testString = 'Hello my name is tom or jack';
$matches = array();
preg_match_all('/\b(tom|jack|alex)\b/i', $testString, $matches);
$result = implode('', $matches[0]);
echo $result; // tomjack

What you’ve tried to do is use a character class syntax ([^s] will match any character but s). But this doesn’t work with series of characters, there’s no such thing as ‘word class’. )