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Date: Wed, 7 Aug 2013 10:43:07 +0100
Subject: Re: Bug? ( () == [] ) != ( ().__eq__([]) )
From: Chris Angelico <rosuav@gmail.com>
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Xref: csiph.com comp.lang.python:52126

On Wed, Aug 7, 2013 at 10:24 AM, Shiyao Ma <i@introo.me> wrote:
> Sorry. I don't quite get it. As you said, it first tries,
> leftOperand.__eq__(rightOperand) then if it returns NotImplemented, it goes
> to invoke rightOperand.__eq__(leftOperand). But for any reason, [] == ()
> returns false, why?

If neither of them has implemented a check, then it's assumed they're
not equal. It wouldn't be helpful for the == operator to return
anything other than True or False (except maybe NaN), so it returns
False.

ChrisA