Wednesday, April 16, 2008

Python: Make division always produce real numbers

A division of 7/3 in Python will gives a result of 2. However, this is not correct. Since Python always assume that the numbers are whole numbers, the result will be truncated from 2.5 to 2.

A work around is to write one or both of the numbers as a decimal:
>>> print 7/3.0

>>> print 7.0/3

>>> print 7.0/3.0
In order to change this behaviour of Python, throughout the program execution, so that Python will always produce real numbers, a module division has to be imported.
>>> from __future__ import division

>>> print 7/3