Stefan Krah <stefan-usenet <at> bytereef.org> writes:
>
> >>> d = {0:Decimal("NaN")}
> >>> Decimal("NaN") in d.values()
> False
>
> So, since non-decimal use cases are limited at best, the equality/inequality
> operators might as well have the behavior of the other comparison operators,
> which is safer for the user.
The problem is when searching for /another/ object which hashes the same as
Decimal("NaN"). Here is a made-up situation to show you the problem:
>>> class H(object):
... def __hash__(self): return hash(1)
... def __eq__(self, other): raise ValueError
...
>>> h = H()
>>> d = {h: ""}
>>> d[1]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 3, in __eq__
ValueError
>>> d[1] = 2
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 3, in __eq__
ValueError
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