$re = '/((\[.*\])?((\'(?:[^\']|\'\')*\'!)|([a-zA-Z0-9_]+!)))?((\$?[a-z]{1,3}\$?[0-9]{1,7})(\:\$?[a-z]{1,3}\$?[0-9]{1,7})?|\$?[a-z]{1,3}\:\$?[a-z]{1,3}|\$?[0-9]{1,7}\:\$?[0-9]{1,7})/mi';
$str = 'A1:B1
A$1:B$12
$A1:$b12
AA11:$BB$11
$A:B
A:$C
12:34
$12:$35
\'hello\'+[ths]ToDoList_1!D26+\'Blank \'\'A1\'\'(2)\'!G14
';
preg_match_all($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