$re = '/[^/\d]*\d[^/]*/m';
$str = '/first/12ab34/B1a234/12B3a/1234/second/A789B-89d';
$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