How to check if float is approximately an integer

Question

In Python, how can I check if a floating point number is approximately a whole number, with a user-specified maximum difference?

I am thinking of something like is_whole(f, eps), where f is the value in question and eps is the allowed maximum deviation, with the following results:

>>> is_whole(1.1, 0.05)
False
>>> is_whole(1.1, 0.2)
True
>>> is_whole(-2.0001, 0.01)
True

Downvote without comment? Nothing I can do to improve then... — Michael Schlottke-Lakemper, Nov 09 '15 at 13:32

Michael Schlottke-Lakemper · Answer 1 · 2015-11-09T12:11:38.093

5

One solution I came up with is

def is_whole(f, eps):
    return abs(f - round(f)) < abs(eps)

but I am not sure if there is a more pythonic way to do this.

EDIT

Use abs(eps) instead of just eps to avoid silent misbehavior.

edited Nov 09 '15 at 12:11

answered Nov 09 '15 at 11:58

Michael Schlottke-Lakemper

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@HighPerformanceMark Thanks for your hint, I've changed the function a little. – Michael Schlottke-Lakemper Nov 09 '15 at 12:11
it is hard to get more pythonic than a natural 1-line function – John Coleman Nov 09 '15 at 12:11

score 1 · Answer 2 · answered Nov 09 '15 at 13:16

I would probably just write a function doing this myself.

def is_whole(f, eps):
    whole_number = round(f)
    deviation = abs(eps)
    return whole_number - deviation <= f <= whole_number + deviation

I wrote this on the fly, if there are mistakes please tell me! Hope I could help.

How to check if float is approximately an integer

2 Answers2