$re = '/^.*?(?=\|)/';
$str = 'uploads/images/adsense.png|uploads/images/tree-7835_960_720.jpg|uploads/images/way-427984_960_720.jpg|uploads/images/friendship-1081843_960_720.jpg|uploads/images/pinky-swear-329329_960_720.jpg';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php