pattern
The grouping pattern. Each dot "." represent one column. If
two or more columns need to be combined in some certain formats, they should
be put together inside a pair of brackets "[ ]". You can add any special
characters, such as "(" and "~", inside the pair of brackets but please
don't leave those special characters outside the brackets. If you want to
add a dot as a special character. Please use "^.^" for every single dot
you would like to add.