Question

Level: Beginner

In the following code my ‘samePoint’ function returns False where i am expecting True. Any hints?

import math

class cPoint:
    def __init__(self,x,y):
        self.x = x
        self.y = y
        self.radius = math.sqrt(self.x*self.x + self.y*self.y)
        self.angle = math.atan2(self.y,self.x)
    def cartesian(self):
        return (self.x, self.y)
    def polar(self):
        return (self.radius, self.angle)

class pPoint:
    def __init__(self,r,a):
        self.radius = r
        self.angle = a
        self.x = r * math.cos(a)
        self.y = r * math.sin(a)
    def cartesian(self):
        return (self.x, self.y)
    def polar(self):
        return (self.radius, self.angle)

def samePoint(p, q):
    return (p.cartesian == q.cartesian)

>>> p = cPoint(1.0000000000000002, 2.0)
>>> q = pPoint(2.23606797749979, 1.1071487177940904)
>>> p.cartesian()
(1.0000000000000002, 2.0)
>>> q.cartesian()
(1.0000000000000002, 2.0)
>>> samePoint(p, q)
False
>>> 

source: MIT OpenCourseWare http://ocw.mit.edu Introduction to Computer Science and Programming Fall 2008

Answer 1

Looking at your code

def samePoint(p, q):
    return (p.cartesian == q.cartesian)

p.cartesian, q.cartesian are functions and you are comparing function rather than function result. Since the comparing two distinct functions, the result is False

What you should have been coding is

def samePoint(p, q):
    return (p.cartesian() == q.cartesian())