$re = '/\d{2}/\d{2}/\d{2,4}$/m';
$str = 'My birthday is 11/13/2018
Another way is to say 11/13/18
And the day after 11/13/2018 is 11/14/2018';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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