>>>distance(6,3)
3
>>>distance(3,6)
3

def distance(x, y):
    if x >= y:
        result = x - y
    else:
        result = y - x
    return result

In [1]: abs(1-2)
Out[1]: 1

In [2]: abs(2-1)
Out[2]: 1

>>> def distance(x,y):
    return abs(x-y)

import numpy as np
a = [1,5,6,8]
np.diff(a)
Out: array([4, 1, 2])

def distance(a, b):
    if (a < 0) and (b < 0) or (a > 0) and (b > 0):
        return abs( abs(a) - abs(b) )
    if (a < 0) and (b > 0) or (a > 0) and (b < 0):
        return abs( abs(a) + abs(b) )

print distance(-25, -15)
print distance(25, -15)
print distance(-25, 15)
print distance(25, 15)

import math

def distance(a, b):
    if (a == b):
        return 0
    elif (a < 0) and (b < 0) or (a > 0) and (b > 0):
        if (a < b):
            return (abs(abs(a) - abs(b)))
        else:
            return -(abs(abs(a) - abs(b)))
    else:
        return math.copysign((abs(a) + abs(b)),b)

print(distance(3,-5))  # -8

print(distance(-3,5))  #  8

print(distance(-3,-5)) #  2

print(distance(5,3))   # -2

print(distance(5,5))   #  0

print(distance(-5,3))  #  8

print(distance(5,-3))  # -8