Learntofish's Blog

A blog about math, physics and computer science

Python 3: Inheritance and super()

Posted by Ed on April 23, 2016

Inheritance in Object Oriented Programming (OOP) means that you create a new class by extending an existing class. For example, suppose we have a class Shape with the attribute position. Then we can create a new class Circle by taking Shape and extending it by a new attribute center:

# Python 3

class Shape(object):
    def __init__(self, position):
        self.position = position

class Circle(Shape):
    def __init__(self, position, radius):
        super().__init__(position)  # call __init__() method of base class Shape
        self.radius = radius

def example():
    c = Circle( [5, 2],  7.0 )
    print("position of circle:", c.position)
    print("radius of circle:", c.radius)

if __name__ == '__main__':
    example()

With super().__init__() we call the __init__() method of the base class Shape. If you run that program the output is

position of circle: [5, 2]
radius of circle: 7.0

References

  1. Youtube video by Charl Botha
  2. Understanding python super with init methods (Stackoverflow)

If you’ve liked this blog post feel free to skim through my other articles here, e.g. I’ve written an introduction to OOP in Python.

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