Week 8 - Linked Lists

Linked lists are a recursive data structure in nature - they either consist of an empty node which consists of None or a cargo that has a reference to another linked list (that can either be a cargo or an empty node and so on)

On a higher level, linked lists are easy to visualize - picture a line of trains where each carriage is attached to its predecessor and the following train by a link, and each carriage contains a cargo.  These carts can be 'infinite' in number, as they can keep linking to new carts (ok fine, that'll never happen in the real world but it's relatively easy to visualize...right?)

Anywho, let's look at Danny's implementation.  The comments are basically me trying to explain what's happening to myself/you:

Just to make it more clear about what's happening in prepend, see the below (badly) drawn diagram.  Note that the star denotes a copy

Once again, see the below for a more clear (I hope), visual explanation

Let's look at the contains method to view how Linked Lists are used with recursion, once again my remarks are in the comments:

In lecture we talked about wrapper classes for lists, which I personally didn't really see the point of, but it basically ...well it wraps the entire linked list into one object that has two parameters - the linked list itself, and the length/size/number of nodes in it....moving on then.

But I got really confused at the reverse function discussed so let me dissect it - once again the comments are my remarks:

Edit:: OH I SEE WHY THE WRAPPER CLASS IS USEFUL!

See the below code and comments: