I found Figure 1-1 on page 11 of the Camel book (3rd Ed.) to give a nice visual explanation on arrays and associative arrays. It aslo helps to see the containment of scalar values within such arrays.
yet another observation:
perl arrays and lists are different in the sense that enclosing a ( ) around a bunch of numbers will concatenate them when used under a comma operator, while
when used under a [ ] they retain their identity.
anything like:
my @data = ( @xvalues, @yvalues )
concatenates xvalues and yvalues. if xvalues/yvalues is an array then they get concatenated.
however if they are lists [ ], they retain their identity.