CODEWITHSUNDEEP
python-2.7python-3.x
Deep_547
Deep_547

Reputation: 17

Python error: unbound method distance() must be called with Point instance as first argument (got classobj instance instead)

On executing the below code 

class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def distance(self,x1,y1,x2,y2):
        d = math.sqrt(((x2 - x1) ** 2) + ((y2 - y1) ** 2))
        print ("Distance between the points is " + "%0.6f" % d)
        return d

def main():
    x = float(input("Enter x coordinate of first circle's centre: "))
    y = float(input("Enter y coordinate of the first circle's centre: "))
    r = float(input("Enter first circle's radius: "))
    pointx1 = x
    pointy1 = y
    first_circle = circle(x, y, r)
    print(first_circle)
    x = float(input("\nEnter x coordinate of second circle's centre: "))
    y = float(input("Enter y coordinate of the second circle's centre: "))
    r = float(input("Enter second circle's radius: "))
    pointx2 = x
    pointy2 = y
    second_circle = circle(x, y, r)
    Point.distance(Point,pointx1, pointy1, pointx2, pointy2)

I get the following error:

File "C:/Users/Deepak/PycharmProjects/Submission/Shapes.py",line 102,in main 
Point.distance(Point,pointx1, pointy1, pointx2, pointy2)
TypeError: unbound method distance() must be called with Point instance as 
first argument (got classobj instance instead)

I am trying to read the center coordinates and radius of two circles from the user and then I am trying to determine the distance between their centers.I tried sending only four parameters to Point.distance() but that also returned an error. Please help.What should I do to resolve this error.

Upvotes: 1

Views: 155

Answers (1)

mikuszefski
mikuszefski

Reputation: 4043

I am not sure if you got wrong what I think you might got wrong, but you do not pass an argument for self, you only pass pointx1, pointy1, pointx2, pointy2, the self is handled internally. Actually your distance function is not really taking advantage of the class structure. You might think of, e.g.:

from math import sqrt

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


    @classmethod
    def two_point_distance(cls, pnt1, pnt2):
        return sqrt( ( pnt1.x - pnt2.x )**2 + ( pnt1.y - pnt2.y )**2 )


    def distance_to(self, pnt2):
        return sqrt( ( self.x - pnt2.x )**2 + ( self.y - pnt2.y )**2 )


pntA=Point(3, 2)
pntB=Point(7, 8)

print Point.two_point_distance( pntA, pntB )
print pntA.distance_to( pntB )

Upvotes: 1

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