Stripping Phrases From Start And End Of Thread Title

[arlarson]

I'm trying to strip some phrases from the beginning and end of a thread title. I'm an amateur with coding, so I'm assuming I'm missing something basic. This doesn't work:

PHP Code:

$newtitle = $vbulletin->GPC['subject'];
$bannedphrases = array ('question on','question for','question about','question','questions');
foreach ($bannedphrases as $word) {
  $i = strlen($word);
    if (substr($newtitle,0,$i) == $word) {$newtitle = substr($newtitle,$i);}
    if (substr($newtitle,-$i,$i) == $word) {$newtitle = substr($newtitle,0,-$i);}
}
$vbulletin->GPC['subject'] = $newtitle; 

I would appreciate any suggestions or tips on how to get on the clue bus. Thanks.