Help with cleaner.php (REGEX)

[The Dawg]

I need to replace an outdated mods text in posts.

Old code example:

[ame="http://www.youtube.com/watch?v=wYJ20INbM7Q"]YouTube - ‪Bill O'Reilly Interviews Rapper Lupe Fiasco - 06/20/11‬‏[/ame]

How I want the new code to look:

[video=youtube;wYJ20INbM7Q]http://www.youtube.com/watch?v=wYJ20INbM7Q[/video]

Regex I was given by a coder:

$text = preg_replace('|\[ame="http://www.youtube.com/watch\?v=([a-z0-9]+)"\](.+)|i', '[video=youtube;$1]http://www.youtube.com/watch?v=$1[/video]', $text);

I do not know where to put this in cleaner.php

I put it here:

PHP Code:

// BACK UP YOUR DATABASE
$replacer = array(
$text = preg_replace('|\[ame="http://www.youtube.com/watch\?v=([a-z0-9]+)"\](.+)|i',
'[video=youtube;$1]http://www.youtube.com/watch?v=$1[/video]', $text) 
);

// BACK UP YOUR DATABASE 


and it does nothing.

Please tell me how to execute this code.

Thanks