Subclassing et al.py

class Point(object):
    def __init__(self, x, y):
        self.x = x
        self.y = y

        # See how I dont have to define these above but should define them in init?
        self.secret = 'hello Burke'
        self.message = None
        self.model_results = list()

    def __repr__(self):
        return "Point<{0}, {1}>".format(self.x, self.y)

    def do_something(self, message):
        self.message = message
        print("If this did something that would be cool instead of just update message. self.message is {0}".format(
            self.message))

    def run_model(self):
        for i in range(0, 5):
            self.model_results.append(i)
            print("  .. {0}".format(i))


class Point3D(Point):
    def __init__(self, x, y, h):
        super(Point3D, self).__init__(x, y)
        self.h = h

    def do_something(self):
        print("We completly overwrote this function")
        return None

    def __repr__(self):
        return "Point3D<{0}, {1}, {2}>".format(self.x, self.y, self.h)

    @property
    def sum_coords(self):
        print("We can also completly essentially add virtual fields")
        return self.x + self.y + self.h


if __name__ == "__main__":
    print("Point 1")
    pt1 = Point(10.0, 20.0)
    print("... but we can also define another obj of the Point type")
    pt2 = Point(34.0, 100.0)

    print("See how the values of pt1.x != pt2.x ? That's because they are different instances of the same class")
    print("pt1.x: {0}".format(pt1.x))
    print("pt1.secret: {0}".format(pt1.secret))
    print("pt2.x: {0}".format(pt2.x))
    print("pt2.secret: {0}".format(pt2.secret))

    print("But I can change values")
    pt2.secret = 'Hello 12222'
    print("pt2.secret is now: {0}".format(pt2.secret))

    # Value of model_results before we run run_model()
    print("Value of model_results BEFORE we run run_model()")
    print(pt1.model_results)
    print("")

    # Classes can do stuff
    print("run the model:")
    pt1.run_model()

    print("Value of model_results AFTER we run run_model()")
    print(pt1.model_results)

    # Repr allows you define what is shown when the obj gets printed
    print("We can also use the __repr__ definition to control how the object prints or is represented as a string")
    print(pt1)

    pt2 = Point(34.0, 100.0)

    # Ok, now lets try that subclass
    pt13d = Point3D(10.0, 20.0, 10.0)
    print(pt13d)
    print("pt13d.secret: {0}".format(pt13d.secret))
    pt13d.do_something()
    print("now run the model, its still there")
    pt13d.run_model()  # See how this still works because the Point3d is subclasses from Point

    print("p13d.sum_coords: {0}".format(pt13d.sum_coords))