$re = '/\b(?P<date>
(?P<day>
(?:(?:0[1-9]|[12]\d|30)(?=[- :\.\/](?:04|06|09|11)))|
(?:(?:0[1-9]|[12]\d|3[01])(?=[- :\.\/](?:01|03|05|07|08|10|12)))|
(?:(?:0[1-9]|[12]\d)(?=[- :\.\/]02[- :\.\/]\d\d(?:([02468][048])|([13579][26])))
(?![- :\.\/]02[- :\.\/](?:([2468][1235679])|([13579][01345789])00)))|
(?:(?:0[1-9]|1\d|2[0-8])(?=[- :\.\/]02[- :\.\/]))
)[- :\.\/]
(?P<month>0[1-9]|1[012])[- :\.\/]
(?P<year>[1-9]\d{3})
)\b/mx';
$str = '';
preg_match_all($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