How accurate is Python's random() function?
Assume I'd like to make a decision based on a 1 / 234276901 probability coin flip, can I still use a
if random() < 1. / 234276901:
statement?
How accurate would such statement be? (in terms of the actual probability the if will be taken).
Is there a more precise (yet running in reasonable time) way to get such coin flips?
random.random() produces a float value in the range [0.0, 1.0) (meaning that 0.0 is included in the possible values, but 1.0 is not).
Floating point numbers have 53 bits of precision, so you get 2 ** 53 different 'steps' between 0.0 and 1.0. 53 bits is plenty of precision to represent 1 / 234276901, which only needs about 28 bits:
>>> 234276901 .bit_length()
28
So yes, using random.random() < 1 / 234276901 will work, there is plenty of precision left over.