Evaluate expression as float in Python

I want to write a function which inputs two variables a, b and which returns a开发者_StackOverflow中文版/b as a float irrespective of the types of a and b. Right now I'm doing this as:

def f(a, b):
    return float(a)/float(b)

Is there a better way to do this?

Assuming you are using Python2, put this at the top of the file

from __future__ import division

now / will always give a float. Use // for the old behaviour.

If you are using Python3, then this is already the default behaviour of /

You could simply force the conversion of one of the operands to the float type, for example:

def f(a, b):
    return (a*1.0)/b

It depends. ;)

The safest way is to do what you have, which will work for every numeric type that can be converted to a float. Some numeric types, such as Fraction in Python 3, will still return a Fraction even with the new division (which only affects ints -- other types define / for themselves) but your code will properly turn Fractions into floats.