Operator overloading is an advanced technique we can use to make classes comparable and to make them work with Python operators.

Let’s take a class Dog:

class Dog:
    # the Dog class
    def __init__(self, name, age):
        self.name = name
        self.age = age

Let’s create 2 Dog objects:

roger = Dog('Roger', 8)
syd = Dog('Syd', 7)

We can use operator overloading to add a way to compare those 2 objects, based on the age property:

class Dog:
    # the Dog class
    def __init__(self, name, age):
        self.name = name
        self.age = age
    def __gt__(self, other):
        return True if self.age > other.age else False

Now if you try running print(roger > syd) you will get the result True.

In the same way we defined __gt__() (which means greater than), we can define the following methods:

• __eq__() to check for equality
• __lt__() to check if an object should be considered lower than another with the < operator
• __le__() for lower or equal (<=)
• __ge__() for greater or equal (>=)
• __ne__() for not equal (!=)

Then you have methods to interoperate with arithmetic operations:

• __add__() responds to the + operator
• __sub__() responds to the - operator
• __mul__() responds to the * operator
• __truediv__() responds to the / operator
• __floordiv__() responds to the // operator
• __mod__() responds to the % operator
• __pow__() responds to the ** operator
• __rshift__() responds to the >> operator
• __lshift__() responds to the << operator
• __and__() responds to the & operator
• __or__() responds to the | operator
• __xor__() responds to the ^ operator

There are a few more methods to work with other operators, but you got the idea.

Lessons in this unit:

0:	Introduction
1:	Functions
2:	Lambda functions
3:	Nested functions
4:	Recursion
5:	Closures
6:	Objects
7:	Classes
8:	Polymorphism
9:	▶︎ Operator overloading