Python - Operator Overloading

With operator overloading feature in Python, we can make operators to work for user-defined classes. As we create a class, it creates a new type in the code and Python allows us to specify the operators with a special meaning for a data type, this ability is known as operator overloading. For example - '+' operator can be overloaded for a string class to concatenate two strings.

Python provides some special function having __ as prefix and suffix in the name, which is also known as Magic method or Dunder method. This function is automatically invoked when the associated operator is used. For example, when + is used, the magic method __add__ is automatically invoked in which the operation for + operator is defined. To change the behavior of the operator, the magic method should be changed which can achieved by defining the magic method in the class.

Example: overloading + operator

The example below describes how to overload + operator to add two vectors. To change the behavior of + operator, magic method __add__ is defined in the class as shown in the example. In the example, the vector v1 is taken as (10, 15) and vector v2 is taken as (5, 25). The addition operation of v1 and v2 creates v3 which returns (10+5, 15+25) or (15, 40).

class vector:
  def __init__(self, x, y):
    self.x = x
    self.y = y
  def __str__(self):
    return "({0},{1})".format(self.x, self.y)
  
  #function for operator overloading
  def __add__(self, other):
    X = self.x + other.x
    Y = self.y + other.y
    return vector(X, Y)

#creating vector objects
v1 = vector(10, 15)
v2 = vector(5, 25)

#using overloaded + operator 
#on vector objects
v3 = v1 + v2

#displaying the result
print("v3 =", v3)

The output of the above code will be:

v3 = (15,40) 

Overloadable operators in Python

Following is the list of operators that can be overloaded in Python.

Binary Operators

Comparison Operators

Assignment Operators

Unary Operators

Operator Overloading Examples

Here is the list of various operator overloading examples which can be used to understand the concept more deeply.