Python Infinity - Any caveats?

Question

So Python has positive and negative infinity:

float(\"inf\"), float(\"-inf\")

This just seems like the type of feature that has to have som

Answer 1

I found a caveat that no one so far has mentioned. I don't know if it will come up often in practical situations, but here it is for the sake of completeness.

Usually, calculating a number modulo infinity returns itself as a float, but a fraction modulo infinity returns nan (not a number). Here is an example:

>>> from fractions import Fraction
>>> from math import inf
>>> 3 % inf
3.0
>>> 3.5 % inf
3.5
>>> Fraction('1/3') % inf
nan

I filed an issue on the Python bug tracker. It can be seen at https://bugs.python.org/issue32968.

Update: this will be fixed in Python 3.8.