[Python-Dev] decimal.py: == and != comparisons involving NaNs

Mark Dickinson dickinsm at gmail.com
Mon Nov 9 13:40:06 CET 2009

On Mon, Nov 9, 2009 at 12:21 PM, Stefan Krah <stefan-usenet at bytereef.org> wrote:
> I see the point, but Decimal("NaN") does not hash:
>>>> hash(Decimal("NaN"))
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
>  File "/usr/lib/python2.7/decimal.py", line 937, in __hash__
>    raise TypeError('Cannot hash a NaN value.')
> TypeError: Cannot hash a NaN value.

I think that may represent an excess of caution.  float nans do hash quite
happily, and I can't see a good reason for preventing Decimal nans from
having a hash.


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