Python logarithm math strange result

Question

What is the explanation for this unexpected results in Python??!;

from math import *
>>>log(1000,10) ## expecting 3.0
2.9999999999999996
>>>1000**(1/3) ## expecting 10.0
9.999999999999998

Answer 1

Basically value of these functions are calculated using some series. As python by default uses floating values, so it calculates values very precisely. You can see this...

Efficient implementation of natural logarithm (ln) and exponentiation That`s why it gives these types of result. You can use Fraction class from fractions to convert these values to integer.

https://docs.python.org/3.1/library/fractions.html