Gedeelte van link gebruiken.

$string = 'http://www.youtube.com/watch?v=zOpF_ZGD4Ps'; 
$v = end( explode('http://www.youtube.com/watch?v=',$string) ); 
   
echo ($v); 

$string = 'http://www.youtube.com/watch?v=zOpF_ZGD4Ps'; 
$v = end( explode('http://www.youtube.com/watch?v=',$string) ); 
 
echo ($v);

$string = "http://ash-v47.ash.youtube.com/get_video?video_id=zOpF_ZGD4Ps"; 

$code = end(explode("=", $string)); 

$string = "http://ash-v47.ash.youtube.com/get_video?video_id=zOpF_ZGD4Ps"; 
 
$code = end(explode("=", $string));

<?php
$v = array_pop(explode('=', 'http://ash-v190.ash.youtube.com/get_video?video_id=np5JeJeVW Ck'));
echo $v;
?>

<?php
$v = array_pop(explode('=', 'http://ash-v190.ash.youtube.com/get_video?video_id=np5JeJeVW Ck'));
echo $v;
?>