$re = '/((1?\d(?::\d\d)?(?: [ap]\.m\.)?)(?:-(?2))?)/i';
$str = '9:30-11 a.m. asdflkj; 12-8 p.m. 2:30-4:30 p.m. as;dlfkj 8 p.m. asdf;lkj 7-11 p.m. 11 a.m.-1 p.m. asd;lfkj 11 a.m. asd;flkj 7-10:30 p.m. and 8 p.m.-12 a.m.
asdf;lkj 12:30-2:30 p.m. a;lsdfj 12:15 p.m. a;ljkf 7 p.m.-12 a.m. 9:30-11:30 a.m.
8:00 a.m.-12:45 p.m.';
preg_match_all($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