hyperlink - php preg_replace reuse of subject -

i've got big problem , can me out...

i'd code plugin. plugin should search on website (for example www.example.com/index.php specific word example number1. afterwords word found should replaced hyperlink. link should guide extern website example www.example2.com/index.php.

according current website, found word should added hyperlink. if current site www.example.com/index.php , found word number1, hyperlink should this:

www.example2.com/index.php/number1 

and shouldn't same hyperlink, created dynamic word plugin finds.

beneath current code. hope can me out. thanks.

public function oncontentprepare($context, &$row, &$params, $page = 0) {     $text = $row->text;          $pattern = array();     $pattern[0] = '/number1/';     $pattern[1] = '/number2/';     $pattern[2] = '/number3/';      $subject = array();     $subject[2] = 'https://www.example.com/index.php/';     $subject[1] = '(...)';     $subject[0] = '(...)';      $row->text = preg_replace($pattern,$subject,$text); }