[erlang-questions] Warning: erlang:phash2 output

Bjorn Gustavsson <>
Thu May 7 09:26:32 CEST 2009


2009/5/7 Paulo Sérgio Almeida <>:
> Martin Bjorklund wrote:
>
>> Actually, phash2 uses a great hash function (by Robert Jenkins), if
>> you know how to invoke it -- you need to call it with a binary to get
>> this algorithm.

Actually, it produces good hash values for any term *except* atoms.

If you have term that contains atoms (e.g. atoms in a list or tuple), you
will probably get a decent hash value anyway because the hash for
the atoms is mixed into the hash value calculated by the list or the
tuple.

Try:

erlang:phash2([a]).
erlang:phash2([b]).
erlang:phash2([c]).

/Bjorn
-- 
Björn Gustavsson, Erlang/OTP, Ericsson AB



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