Arrays and hashes can be thought of as letter boxes in a street which stores data. An array uses the street number to identify each letter box. A hash uses a name (which can be a number) to identify each letter box.

Note that letter boxes can't have big parcels of data in them. In fact, in Perl a letter box (scalar) can have only one item of data, but that item can have the address of another letter box (generally in a different street) or often just a street name (reference to another array of hash).