我正在努力让它工作，但没有。怎么了？

$tutorgeocodesrc = "http://where.yahooapis.com/geocode?location=" . urlencode($tutoraddressfull) . "&appid=...";
$tutorgeocode    = simplexml_load_file($tutorgeocodesrc);
$tutorlat        = $tutorgeocode->Result[0]->latitude;
$tutorlng        = $tutorgeocode->Result[0]->longitude;
foreach($tutorgeocode->Result[0]->latitude as $child) 
{
    update_post_meta($user_id, \'tutorcords\', $tutorlat);
}