Class "hexmode" consists of integer vectors with that class
attribute, used merely to ensure that they are printed in hex. If width = NULL (the default), the output is padded with
leading zeroes to the smallest width needed for all the non-missing
elements.
as.hexmode can convert integers (of type "integer" or
"double") and character vectors whose elements contain only
0-9, a-f, A-F (or are NA) to class
"hexmode".
There is a ! method and |, & and
xor methods: these recycle their arguments to the
length of the longer and then apply the operators bitwise to each
element.