The answer to your first question is no. Neither is correct. Hash values can only be scalars. If you want to store multiple values, you need to store a reference (see References Quick Reference) to another data structure.

As for your second question, both will work. The first works best when you're accessing an array slice -- multiple elements at once -- or when you want to evaluate that part of the expression in list context. The second is more useful most of the time, especially if you don't yet know about slices or why you'd want to do it.

I'd prefer this syntax for accessing a single element though: