I'm studying and practicing Python right now. I'm kinda scared by the concept of classes in it and I'm stuck wondering how to implement data structures like Linked Lists, Graphs and Trees.
I've heard from many that these are the most important data structures asked in interviews and coding competitions.
So my question is, Is there a way to implement all the said data structures without using classes and just by using predefined data structures like lists, dictionaries etc?
If we are being pedantic, everything in python is a class, so you can't avoid them. If you are concerned about everything that goes into creating your own class, like which methods should be defined where, that's something we can focus on. In fact, there is no general consensus on the boundaries to any given class and popular programs like C and Go don't even have them.
An alternative is to just use a dict to hold key/value pairs. Roughly, a class is just a dictionary with associated methods anyway. Dictionary keys can hold a wide variety of objects (as long as they are hashable) whereas class attributes must be strings and are further restricted to fit lexicographically in a program. A linked list for instance could be { "next object":obj, "previous object":obj, "item":obj } or even a list [obj, obj, obj] and your code remembers what those indexes are.
But classes are very convenient, especially when implementing other data structures. It makes sense that methods manipulating a linked list node would be on the node itself. There isn't much to gain avoiding classes when they are reasonable data structures to use.
There are plenty of modules out there that implemente linked lists, trees and graphs. Unless this is an exercise in learning data structures, some time spent with your favorite search engine is the best option of all.
