$re = '/(?<!\d)(\d{1,2}[/. ](?:\d{1,2}|(?:J(?:an(?:uary)?|u(?:ne?|ly?))|Feb(?:ruary)?|Ma(?:r(?:ch)?|y)|A(?:pr(?:il)?|ug(?:ust)?)|Sep(?:t(?:ember)?)?|(?:Nov|Dec)(?:ember)?|Oct(?:ober)?))[/. ]\d{2}(?:\d{2})?)(?!\d)/m';
$str = 'dasndljaksdhfinwejfiv 12/05/2018\'\', \'akdhaouiyfbh adv12.03.2019\',\'faytdvi advonalsdnfoaidv 5/9/2019IUAYFNVVKNVAIUEHF';
preg_match_all($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