An Object By Any Other Name Would Still Be Confusing 

I’ve spent all of last week trying to wrap my mind around Object Oriented Programming in general and in Python specifically and here are my notes:

Everything in Python is an Object! Strings are objects, Dictionaries are objects, Lists are objects, Integers are objects…get the picture?

Objects: are copies of classes which contain attributes and methods.

Classes: a blueprint of a thing; it’s used by following its directions to build a thing; it can be used to make one thing or thousands of things. Takes a hard/complicated problem and breaks it up into smaller pieces that hide their complexity from the rest of the program

Attributes/variable: assignment; describes the thing

Methods/function: code; defines what the thing can do; the things behavior

self: an alias to the instance/object; a temporary placeholder; points to the specific object

__init__: constructor; defines the state of a thing when it gets created; automatically calls the classes’ predefined __init__ methods at creation

Object/Instance: a bit of self-contained code and data; is the thing that is created by following the instructions from the blueprint

Inheritance: an object that is created to take on the characteristics and functionality of another class while adding object specific characteristics and functionality; a child may inherit their father’s eye color yet the child also is a unique person, with its own characteristics and functionality and is not its father.

class Person(object):

    def create_name(self, name): #once the objects are created, self is replaced with person1 or person2. name is replaced Sam or Harry 
        self.name = name #sets the objects first or second to the name Sam or Harry
    def display_name(self):
        return self.name #returns either Sam or Harry
    def saying(self):
        print 'Hello, %s' % self.name #prints Hello, Sam or Harry
        
person1 = Person() #creates a person1 object 
person2 = Person() #creates a person2 object

person1.create_name('Sam') #sets the person1 object's name to Sam
person2.create_name('Harry') #sets the person2 object's name to Harry
person1.display_name() #returns Sam
person1.saying() #prints Hello, Sam

 

class DeathMatch(object):
    
    def __init__(self):
        self.lives = 3
        print 'I have %s lives to start with' % self.lives
        
number_of_lives = DeathMatch() #starts the player with 3 lives without having to take an additional step to call the function

 

class Father(object):
    eyes = "blue"
    height = "6\'3\""
    
class Daughter(Father): # Daughter inherits all the attributes of the Father class
    height = "5\'6\"" #Daughter's height will override the inherited Father's height
    

sarah = Daughter()
print sarah.eyes
print sarah.height

References: