Question

Possible Duplicate:
Why doesn’t this division work in python?

I have this and works fine

def roi(stake, profit):
    your_roi = profit / stake * 100
    return your_roi

def final_roi():
    roi1 = roi(52, 7.5)
    print "%.2f"  % roi1

final_roi()

but if I change the profit number to an int (meaning both stake and profit will have an int value) e.g. 52, 7 it is giving the output of 0.00. what’s wrong there? I thought it had been formatted to be a float with the precision of two.

Answer 1

In python2.x, / does integer division (the result is an integer, truncated downward) if both arguments are of type integer. The “easy” fix is to put:

from __future__ import division

at the very top of your script, or to construct a float out of one of the arguments before dividing:

your_roi = float(profit) / stake * 100

Python also has an integer division operator (//), so you can still perform integer division if desired — even if you from __future__ import division