Your requirement is not entirely clear to me, but you may want to look at the Storable module. In some simple cases, the Data::Dumper also makes it possible to create persistent data on disk.

For more complicated cases, you may also want to take a look at CPAN modules dealing with JSON or Yaml data formats.

But maybe I did not understand well your requirement and you don't need data persistence. If you were only asking about which in-memory data structure to use, then you might have to give a bit more details.