$re = '/^(?:\+971|00971|0)?(?:50|51|52|55|56|2|3|4|6|7|9)\d{7}$/m';
$str = '00971551234567
+971551234567
+97141234567
0551234567
041234567
';
$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