playing with circles

I decided to tinker with inheritance, decoration and using command line arguments. My subject of choice, Circles!

To run the following script at command line:

E.g.
python circles.py 1 1 1

Import to use in a python shell:

from circles import *
c1 = Circle(1)
c2 = Circle3D(1, 1)
c3 = Ellipsoid(1, 1, 1)

#functions
help(c1) #etc

#E.g.
c1.area()
c2.cone_volume()
c3.ellipse_volume()

the code

#!/usr/bin/python3
"""
This module is my example of decoration and inheritance.
Interesting feature of this code is the use of @wraps from functools to ensure the 
method docstrings are passed through decoration.

This module includes 3 classes providing methods for analysing 1d, 2d and 3d circle objects.
1) Circle: diameter, area, perimeter
2) Circle3D: introduces height dimension and calculates things like a cone or cylinder
3) Ellipsoid: Introduces a third variable, depth, to calculate an ellipsoidal shape.
"""
# import modules
import math
from functools import wraps

# decorator to pretty print
def formatter(func):
    @wraps(func)
    def inner(*args):
        return "{} = {:.2f}".format(func.__name__, func(*args))
    return inner


class Circle(object):
    """
    Create a circle and calculate attributes.
    Requires 1 argument: radius
    Result is a formatted string: 'method = value'

    Examples
    >>> Circle(1).diameter()
    'diameter = 2.00'
    >>> Circle(1).area()
    'area = 9.87'
    >>> Circle(1).perimeter()
    'perimeter = 6.28'
    """
    def __init__(self, radius):
        self.radius = float(radius)

    @formatter    
    def diameter(self):
        """multiply radius by 2 to find diameter"""
        return self.radius * 2

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

    @formatter
    def perimeter(self):
        return (2 * math.pi) * self.radius


class Circle3D(Circle):
    """
    Calculate 3 dimensional attributes by building on to the Circle class.
    Requires 2 arguments: radius, height
    Result is a formatted string: 'method = value'

    Examples
    >>> Circle3D(1,1).cylinder()
    'cylinder = 3.14'
    >>> Circle3D(1,1).cone_volume()
    'cone_volume = 1.05'
    >>> Circle3D(1,1).cone_area()
    'cone_area = 7.58'
    >>> Circle3D(1,1).sphere_volume()
    'sphere_volume = 4.19'
    >>> Circle3D(1,1).sphere_area()
    'sphere_area = 12.57'
    """
    def __init__(self, radius, height):
         self.height = float(height)
         super(Circle3D, self).__init__(radius)

    @formatter
    def cylinder(self):
        return (math.pi * (self.radius ** 2)) * self.height

    @formatter
    def cone_volume(self):
        return 1/3 * (math.pi * (self.radius ** 2)) * self.height

    @formatter
    def cone_area(self):
        return math.pi * self.radius * (self.radius + math.sqrt(self.height**2 + self.radius**2)) 

    @formatter
    def sphere_volume(self):
        return (4/3) * (math.pi * (self.radius ** 3))

    @formatter
    def sphere_area(self):
        return 4 * (math.pi * (self.radius ** 2))


class Ellipsoid(Circle3D):
    """
    Calculate area and volume of an ellipse and ellipsoid.
    Requires 3 arguments: radius, height and depth
    depth is required for calculating volume of ellipsoid.
    radius and depth define the cross section of the ellipse.
    height defines the overall length/latidudinal dimension.

    Examples
    >>> Ellipsoid(1,1,1).ellipse_area()
    'ellipse_area = 1.57'
    >>> Ellipsoid(1,1,1).ellipse_volume()
    'ellipse_volume = 2.09'
    """
    def __init__(self, radius, height, depth):    
        self.depth = float(depth)
        super(Ellipsoid, self).__init__(radius, height)

    @formatter
    def ellipse_area(self):
        return math.pi * self.radius * (self.height / 2)

    @formatter
    def ellipse_volume(self):
        return (4/3) * math.pi * (self.height / 2) * self.radius * self.depth


if __name__ == "__main__":
    import math, sys, doctest
    doctest.testmod()
    circ = Ellipsoid(sys.argv[1], sys.argv[2], sys.argv[3])
    print(circ.diameter())
    print(circ.area())
    print(circ.perimeter())
    print(circ.cylinder())
    print(circ.cone_volume())
    print(circ.cone_area())
    print(circ.sphere_volume())
    print(circ.sphere_area())
    print(circ.ellipse_area())
    print(circ.ellipse_volume())