Python division

Question

I was trying to normalize a set of numbers from -100 to 0 to a range of 10-100 and was having problems only to notice that even with no variables at all, this does not evalu

Answer 1

You're using Python 2.x, where integer divisions will truncate instead of becoming a floating point number.

>>> 1 / 2
0

You should make one of them a float:

>>> float(10 - 20) / (100 - 10)
-0.1111111111111111

or from __future__ import division, which the forces / to adopt Python 3.x's behavior that always returns a float.

>>> from __future__ import division
>>> (10 - 20) / (100 - 10)
-0.1111111111111111

Answer 2

In python cv2 not updated the division calculation. so, you must include from __future__ import division in first line of the program.

Answer 3

You need to change it to a float BEFORE you do the division. That is:

float(20 - 10) / (100 - 10)

Answer 4

Either way, it's integer division. 10/90 = 0. In the second case, you're merely casting 0 to a float.

Try casting one of the operands of "/" to be a float:

float(20-10) / (100-10)

Answer 5

Specifying a float by placing a '.' after the number will also cause it to default to float.

>>> 1 / 2
0

>>> 1. / 2.
0.5

Answer 6

Make at least one of them float, then it will be float division, not integer:

>>> (20.0-10) / (100-10)
0.1111111111111111

Casting the result to float is too late.