Polymorphism

Polymorphism is one of the four principles of object-oriented programming (OOP). It promotes dynamic inheritance of child classes from their parent class in order to make use of these features themselves in code.

With polymorphism, child classes are able to inherit methods from their parent class for use. This ability to inherit functionality from parent classes not only speeds up the development process, but also helps us reason and understand our code more intuitively as we can see the correlation between objects for easier understanding and manipulation of source code.

from math import pi

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

  def area(self):
    pass

  def fact(self):
    return "I am a two-dimensional shape."

  def __str__(self):
    return self.name

class Square(Shape):
  def __init__(self, length):
    super().__init__("Square")
    self.length = length

  def area(self):
    return self.length**2

  def fact(self):
    return "Squares have each angle equal to 90 degrees."

class Circle(Shape):
  def __init__(self, radius):
    super().__init__("Circle")
    self.radius = radius

  def area(self):
    return pi*self.radius**2

a = Square(4)
b = Circle(7)

print(b)
print(b.fact())
print(a.fact())
print(b.area())