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 evaluate the way I would expect it to:

>>> (20-10) / (100-10)
0
Float division doesn't work either:

>>> float((20-10) / (100-10))
0.0
If either side of the division is cast to a float it will work:

>>> (20-10) / float((100-10))
0.1111111111111111
Each side in the first example is evaluating as an int which means the final answer will be cast to an int. Since 0.111 is less than .5, it rounds to 0. It is not transparent in my opinion, but I guess that's the way it is.

What is the explanation?
Oct 13, 2018 in Python 724 views

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
• 13,300 points

Number division in python

For Python 3, use the // operator: q = ...READ MORE

What is Python division

You're using Python 2.x, where integer divisions ...READ MORE

Python error "ZeroDivisionError: division by zero"

Catch the error and handle it: try: ...READ MORE

+1 vote

Python error "ZeroDivisionError: float division by zero"

The error is thrown in this line matchPercentage ...READ MORE

how do i change string to a list?

suppose you have a string with a ...READ MORE

how can i randomly select items from a list?

You can also use the random library's ...READ MORE

+1 vote

how can i count the items in a list?

Syntax :            list. count(value) Code: colors = ['red', 'green', ...READ MORE