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From: Marko Rauhamaa <marko@pacujo.net>
Newsgroups: comp.lang.python
Subject: Re: Dict when defining not returning multi value key error
Date: Fri, 01 Aug 2014 18:39:30 +0300
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Chris Angelico <rosuav@gmail.com>:

>> but hash(x) == hash(y) does NOT imply that x == y.
>
> Hello, pigeonhole principle :) If this were false - that is, if equal
> hashes DID imply equal objects - it would be necessary to completely
> encode an object's state in its hash, and hashes would be impossibly
> large. This would, in fact, destroy their value completely.

Well, modern computing assumes precisely:

   hash(x) == hash(y) => x == y

That principle is at play with strong authentication (HTTPS et al),
version control (git et al),

A handful of bits uniquely identify an object regardless of its size.


Marko