Question

I’m calculating the length of a line segment in python, but I don’t understand why one piece of code gives me zero and the other gives the right answer.

This piece of code gives me zero:

def distance(a, b):
    y = b[1]-a[1]
    x = b[0]-a[0]
    ans=y^2+x^2
    return ans^(1/2)

This one gives me the right answer:

import math as math

def distance(a, b):
    y = b[1]-a[1]
    x = b[0]-a[0]
    ans=y*y+x*x
    return math.sqrt(ans)

Thank you.

Answer 1

In your first snippet you have written this:

ans^(1/2)

In Python the power operator is not ^, that’s the XOR-operator. The power operator in Python is **. On top of that, in Python 2.x by default the result of the division of two integers is an integer, so 1/2 will evaluate as 0. The correct way would be this:

ans ** 0.5

And another thing, the function you have implemented here can be done a lot easier with math.hypot:

import math

def distance(a, b):
    return math.hypot(b[0] - a[0], b[1] - a[1])