Question

If I have two strings that are identical in value, is it guaranteed that hash(s1) == hash(s2) without using hashlib? Also, what is the upper bound on the number of digits in the hash?
Is there an alternative to hash that is invertable? I understand hash functions are not meant to be used like this. But a 1-1 mapping from strings to short hexadecimal strings that can be inverted and is guaranteed to be different for each string?

Will this work:

import zlib
# compress
zlib.compress("foo")
zlib.decompress(zlib.compress("foo")) == "foo"  # always true?

Thanks.

Answer 1

YES.

>>>help(hash)
    Help on built-in function hash in module builtins:

    hash(...)
        hash(object) -> integer

        Return a hash value for the object.  Two objects with the same value have
        the same hash value.  The reverse is not necessarily true, but likely.