$re = '/[a-zA-Z0-9_]|\+\+|--|<<|>>|[=+<>^*]=|[\[\](){}.;,!<>+^%]/';
$str = '++
--
==
<=
>=
^=
*=
+=
[
]
(
)
{
}
.
;
,
!
<
>
+
^
%
<<
>>';
preg_match_all($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