Testing for positive infinity, or negative infinity, individually in Python
The "pythonic" way is to go with what's readable and maintainable.
That said, x == float("inf") and x == float("-inf") are slightly more readable to me, and I'd prefer them. math.isinf(x) and x > 0 is faster, but only on the order of about 40 nanoseconds per call.
So unless you're checking a whole lot of numbers, it isn't going to make much of a difference in running time.
there is also numpy
>>> import numpy as np>>> np.isneginf([np.inf, 0, -np.inf])array([False, False, True], dtype=bool)>>> np.isposinf([np.inf, 0, -np.inf])array([ True, False, False], dtype=bool)and then there is general isinf
>>> np.isinf([np.inf, 0, -np.inf])array([ True, False, True], dtype=bool)