in reply to
Re^2: Term document matrix for search engine
in thread Term document matrix for search engine
That sounds like it would defeat the purpose of the assignment.
Take a read through perldata, but IMO the best thing to do is have a small test.pl script on the side where you can play around try things out quickly.
And to understand what your code is doing, I highly recommend use Data::Dumper; and then later in your code, say print Dumper \%hash;. The output from dumper is about the same as code which will create the data structure, so it is really handy for learning. Curly brackets for nested hashes, square brackets for nested arrays.