$re = '/(\d{1,2})(:\d{1,2})?(\s+)?-(\s+)?(\d{1,2})(:\d{1,2})?(am|pm)/mi';
$str = 'bla bla 1:30-2pm bla bla 5-6:30am some text 1-2:15am
bla bla 1:30 - 2pm bla bla 5 - 6:30am some text 1 - 2:15am';
preg_match_all($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