Thanks for stopping by for our final article on Perl lists and hashes. This marks our twelfth issue on the subject (at least until we get to some more advanced techniques later on) and in it, we will look at a few of the functions for manipulating two-dimensional lists, how to create lists with more than two dimensions, and finally, how to make a hash full of lists, which is really quite a handy tool.
In our previous article we created a “database” of a bookshelf with some books on it. We then learned how to add rows to it, add a single column, and automate a process to add columns to every row. Here, we will continue working with the @Bookshelf “database.” Just so you don't have to go seeking out our previous article, here is the list of fields:
Book Number
Author
Title
Genre
Number of Stars (how good the book was in a ranking of 1-5, with five being the best)
Perl Programming 
