Answer by Dan Roberts for Checking if float is equivalent to an integer value in python

You'll want to do the latter. In Programming in Python 3 the following example is given as the most accurate way to compare

def equal_float(a, b):    #return abs(a - b) <= sys.float_info.epsilon    return abs(a - b) <= chosen_value #see edit below for more info

Also, since epsilon is the "smallest difference the machine can distinguish between two floating-point numbers", you'll want to use <= in your function.

Edit: After reading the comments below I have looked back at the book and it specifically says "Here is a simple function for comparing floats for equality to the limit of the machines accuracy". I believe this was just an example for comparing floats to extreme precision but the fact that error is introduced with many float calculations this should rarely if ever be used. I characterized it as the "most accurate" way to compare in my answer, which in some sense is true, but rarely what is intended when comparing floats or integers to floats. Choosing a value (ex: 0.00000000001) based on the "problem domain" of the function instead of using sys.float_info.epsilon is the correct approach.

Thanks to S.Lott and Sven Marnach for their corrections, and I apologize if I led anyone down the wrong path.