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Python Abstract Programming

import math
class Point:

    def __init__(self,x,y):
        self.x = x
        self.y = y

    def move(self,x,y):
        self.x += x
        self.y += y

    def __str__(self):
        return "<"+ str(self.x) + "," + str(self.y) + ">"


class Shape:        
    def __init__(self, centrePoint, colour, width, height):
        self.centrePoint = centrePoint
        self.colour = colour
        self.width = width
        self.height = height
        self.type = "Square"

    def __init__(self, centrePoint, radius, colour):
        self.type = "Circle"
        self.radius = radius
        self.colour = colour
        self.centrePoint = centrePoint

    def move(self,x,y):
        self.centrePoint.move(x,y)

    def getArea(self):
        if (self.type == "Square"):
            return self.width * self.height
        elif (self.type == "Circle"):
            return math.pi*(self.radius**2)

    def __str__(self):
        return "Center Point: " + str(self.centrePoint) + "\nColour: "+ self.Colour + "\nType: " + self.type + "\nArea: " + self.getArea()


class Rectangle (Shape):

    def scale(self, factor):
        self.scaleVertically(factor)
        self.scaleHorizontally(factor)

    def scaleVertically(self, factor):
        self.height *= factor

    def scaleHorizontally(self, factor):
        self.width *= factor

class Circle (Shape):

    def scale(self, factor):
        self.radius * factor

This is the code that I still have. Shape is supposed to represent an abstract class, and the other two classes should inherit it, for me it still looks too hardcoded as an abstract solution, how can I improve?

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2 answers

I would change this part in an abstract class:

def getArea(self):
    if (self.type == "Square"):
        return self.width * self.height
    elif (self.type == "Circle"):
        return math.pi*(self.radius**2)

You can specify a default value in an abstract class and override the method in Rectangleor in Circle.

But you can get a better answer at https://codereview.stackexchange.com/ .

UPDATE (example):

from abc import ABCMeta, abstractmethod

class Shape: 
  __metaclass__ = ABCMeta

  @abstractmethod
  def getArea(self):
    pass

class Rectangle (Shape):
  def getArea(self):
    return self.width * self.height

class Circle (Shape):
  def getArea(self):
    return math.pi*(self.radius**2)

UPDATE 2 (overload functions)

Ohad, python, init funtion:

def Shape:
  def __init__(self, centrePoint, colour, **kwargs):
    self.centrePoint = centrePoint
    self.colour      = colour
    self.width       = kwargs.get('width')
    self.height      = kwargs.get('height')
    self.radius      = kwargs.get('radius')


rect = Rectangle(0, "red", width=100, height=20)
circ = Circle(0, "blue", radius=5)

kwargs : , Python?

, :

>>> rect = Rectangle(...)
>>> print isinstance(rect, Rectangle)
True
>>> print isinstance(rect, Circle)
False
+4

-, , python , :

class Shape:        
    def __init__(self, centrePoint, colour, width, height):
        ...

    def __init__(self, centrePoint, radius, colour):
        ...

, .

Base/Abstract ( python, lower_case_with_underscores , camleCase):

class Shape: 
  __metaclass__ = ABCMeta

  @abstractmethod
  def get_area(self):
    pass

  move, scale, scale_vertically, scale_horizontally, print...

, , ( " , .." ) , , , . : Rectangle, Circle ..

+2

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