$re = '/^(\+)|[^\d\n]+/m';
$str = '(639)-234-2323
(042)-982-2234
0974829-928
+83246-983-34
+836(737)-898+78';
$subst = "\1";
$result = preg_replace($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