Classes and Inheritance

Defining

class MyNewClass:
    pass

# Class Instantiation
my = MyNewClass()

Constructors

class Animal:
    def __init__(self, voice):
        self.voice = voice

cat = Animal('Meow')
print(cat.voice)    # => Meow

dog = Animal('Woof')
print(dog.voice)    # => Woof

Method

class Dog:

    # Method of the class
    def bark(self):
        print("Ham-Ham")

charlie = Dog()
charlie.bark()   # => "Ham-Ham"

Class Variables

class MyClass:
    class_variable = "A class variable!"

# => A class variable!
print(MyClass.class_variable)

x = MyClass()

# => A class variable!
print(x.class_variable)

Super() Function

class ParentClass:
    def print_test(self):
        print("Parent Method")

class ChildClass(ParentClass):
    def print_test(self):
        print("Child Method")
        # Calls the parent's print_test()
        super().print_test()

---

>>> child_instance = ChildClass()
>>> child_instance.print_test()
Child Method
Parent Method

repr() method

class Employee:
    def __init__(self, name):
        self.name = name

    def __repr__(self):
        return self.name

john = Employee('John')
print(john)  # => John

User-defined exceptions

class CustomError(Exception):
    pass

Polymorphism

class ParentClass:
    def print_self(self):
        print('A')

class ChildClass(ParentClass):
    def print_self(self):
        print('B')

obj_A = ParentClass()
obj_B = ChildClass()

obj_A.print_self() # => A
obj_B.print_self() # => B

Overriding

class ParentClass:
    def print_self(self):
        print("Parent")

class ChildClass(ParentClass):
    def print_self(self):
        print("Child")

child_instance = ChildClass()
child_instance.print_self() # => Child

Inheritance

class Animal:
    def __init__(self, name, legs):
        self.name = name
        self.legs = legs

class Dog(Animal):
    def sound(self):
        print("Woof!")

Yoki = Dog("Yoki", 4)
print(Yoki.name) # => YOKI
print(Yoki.legs) # => 4
Yoki.sound()     # => Woof!

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