TIL #126 – Hash of infinity

Hash of infinity

Today I learned that the values float("inf") and float("-inf") have two very special hashes:

>>> hash(float("inf"))
314159
>>> hash(float("-inf"))
-314159

In case you can't tell, those are the first few digits of the mathematical constant \(\pi\):

>>> import math
>>> math.pi
3.141592653589793
## ^^^^^

I learned about this during the CPython panel held at EuroPython 2025, after the hosts Łukasz & Pablo asked the panel if they know what the hash of -1 was.

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