$re = '/\b[a-zA-Z0-9 ]+\d+\b/im';
$str = 'Enter Room/Area^_^Area 100#_#Enter Grid^_^Grid2#_#Enter Level / Building^_^Building1#_#Enter Drawing^_^Drawing1#_#Enter Spec section^_^Spec2#_#Enter BOQ^_^BOQ1#_#';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($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