subclass 7/2/18

A good example of subclass i learned today:

import mathclass Circle:
    def __init__(self,radius):
        self.radius = radius

    def area(self):
        return self.radius ** 2* math.pi
    def __repr__(self):
        return '%s has area %s' (self.__class__.__name__, self.area())
class Donut(Circle):
    def __init__(self, outer, inner):
        Circle.__init__(self, outer)
        self.inner = inner
    def area(self):
        outer, inner = self.radius, self.inner
        return Circle(outer).area()-Circle(inner).area()


gdonut = Donut(5,3)
gdonut.area()  # 50.26548245

Thoughts : 

1) kids can inherit some thing, but they can create more than adult, don't be retrain by the Parent class.

2) Don't afraid of you have many subclass/kids, if they are helpful/useful. 

I will accordingly modify/improve my first class application code now!!