[Basic] How To Create Classes In Python [ Object Oriented Programming ]

Let's start by explaining one thing at a time...


Classes in python, are a way to bundle data [information that is fed to the code, or that you 'hard-code' yourself], with associated code, making it easier to manage the code itself and fix bugs if they ever arise. They can help by allowing you to model the problem you’re trying to solve and manage a program’s complexity better.


Let's say you're creating a fighting game where there are two types of NPC's. Bystanders, and fighters. You'd create the "bystander" class as easily as this:

class Bystander:

    pass

You've created the Bystander class. Why is this so great? Because this means that you can set this class to as many variables as you want, and you'll be able to have numerous different "versions" or "instances" of each:

bobby = Bystander()

sarah = Bystander()

"bobby" and "sarah" Are two different "instances" of the same class called "Bystander".

They are what are known as objects. Individual "occurances" or "copies" of the same class. You'll understand why this is so cool in a minute.

Let's modify our class a bit to get a better grasp of what we're dealing with here.

# We created the class called "bystander".
class Bystander:
# Here, we'll have a docstring. They're good for telling what
# our classes do.

"""A Simple Bystander class. These Individuals all have their own greeting."""
    # Now we create what's known as a "constructor" [__init__]
    # Which allows us to take the variables that are passed to the
    # class when the object is "instantiated" or "created".
    # It uses self because it is actually referring to the variable
    # that you use to create the objects.

    def __init__(self, name, greeting = ""):

        self.name = name
        self.greeting = greeting

 #Then we instantiate our objects.
bobby = Bystander("Bobby", "Hiya!")

sarah = Bystander("Sarah", "Konnichi wa!")
 # Notice that Alex doesn't have a greeting, but there will not be an error.
 # That's because the greeting is a "kwarg" or a "keyword argument". It
 # Is an optional argument or "parameter" that can be passed.
alex = Bystander("Alex")
# Please note that no matter how many objects we have, we'll always
# know what objects of this specific class are capable of in the case of 'Methods'.

A Method is a function of a class that is made specifically to be associated with the class itself. Methods must always take the "self" parameter because when it uses "self" it is actually referring to the object itself.

class Bystander:

""" A Simple Bystander class. These individuals have their own greeting."""

def __init__(self, name, greeting = ""):

self.name = name
self.greeting = greeting 

def say_Name(self):

print(self.greeting + " My name is", self.name + ".") 

bobby = Bystander("Bobby", "Hiya!")

bobby.say_Name()

Kira = Bystander("Kira", "Oh, yeah, baby!")

Kira.say_name()

Running this through the interpretor, we should get:

Hiya! My name is Bobby.
Oh yeah, baby! My name is Kira.

I hope this should provide a basic enough insight on how classes and objects are made. I'll leave the rest up to your imagination.