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
views:
118answers:
3
+8
A:
This will be fixed in Python 3.0, for the time being you can use:
from __future__ import divison
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
sukhbir
2010-10-03 18:28:27
I'm not sure that it needs to be 'fixed' - the integer division works as it's supposed to do. Plus Python 3 has been out for almost 2 years...
Scott Griffiths
2010-10-03 18:34:20
I will quote PEP238, `This makes expressions expecting float or complex results error-prone when integers are not expected but possible as inputs.` Also I doubt that he would be using Python 3.0 since I guess everyone makes it clear to stick to 2.6 for now. But I am also learning, so I maybe wrong.
sukhbir
2010-10-03 18:36:57
Many languages use integer division the Python 2 way (which isn't surprising if they lack dynamic typing). I guess that it was considered a design flaw though, or it wouldn't have been changed :) Btw the latest versions are 2.7 and 3.1 (with 3.2 already in alpha).
Scott Griffiths
2010-10-03 18:45:53
+4
A:
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])
Ivo van der Wijk
2010-10-03 18:29:47
+8
A:
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])
Ofri Raviv
2010-10-03 18:29:48