Why is this division not performed correctly?

Question

I've a strange issue in Python: the division is not performed correctly:

print pointB[1]
print pointA[1]
print pointB[0]
print pointA[0]
print  (pointB[1]-pointA[1]) / (pointB[0]-pointA[0])

These are the results:

100
50
100
40
0

thanks

Answer 1

The above behavior is true for Python 2. The behavior of / was fixed in Python 3. In Python 2 you can use:

from __future__ import division

and then use / to get the result you desire.

>>> 5 / 2
2
>>> from __future__ import division
>>> 5 / 2
2.5

Since you are dividing two integers, you get the result as an integer.

Or, change one of the numbers to a float.

>>> 5.0 / 2
2.5

Answer 2

It is done correctly.

50/60 = 0

Maybe you are looking for 50.0/60.0 = 0.83333333333333337, you can cast your variables to float to get that:

print  float(pointB[1]-pointA[1]) / (pointB[0]-pointA[0])

Answer 3

This is how integer division works in python. Either use floats or convert to float in your calculation:

float(pointB[1]-pointA[1]) / (pointB[0]-pointA[0])