>> Also, I believe that max "reasonable" integer range of no collision >> is (-2305843009213693951, 2305843009213693951), ...
> Any range that does _not_ contain both -2 and -1 (-1 is an annoying > special case, with hash(-1) == hash(-2) == -2), and spans no more than > sys.hash_info.modulus integers. Apart from that, the sign and > magnitude of the start of the range don't matter; e.g., > > >>> len(set(hash(i) for i in range(10**5000, 10**5000 + 1000000))) > 1000000 > >>> len(set(hash(i) for i in range(-10**5000, -10**5000 + 1000000))) > 1000000 Sorry again! That only shows that the hash codes are unique. Dicts and sets use only the last N bits to determine the start of the probe sequence, for some value of N >= 3 (depending on the table size). So for a table of size a million, the last 20 bits (1000000 ~= 2**20) are interesting. But same thing: >>> MASK = (1 << 20) - 1 >>> len(set(hash(i) & MASK for i in range(-10**5000, -10**5000 + 1000000))) 1000000 >>> len(set(hash(i) & MASK for i in range(-10**5000, -10**5000 + 1000000))) 1000000 _______________________________________________ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/BXHOS73YMJDSVZUM74VYXXYN5WW63BZ4/ Code of Conduct: http://python.org/psf/codeofconduct/
