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Thu Mar 25 02:15:58 CET 2010 · https://mail.python.org/pipermail/python-dev/2010-March/098864.html

On Wed, Mar 24, 2010 at 2:09 PM, Mark Dickinson <dickinsm at gmail.com> wrote:
> Slight change of topic.  I've been implementing the extra comparisons
> required for the Decimal type and found an anomaly while testing.
> Currently in py3k, order comparisons (but not ==, !=) between a
> complex number and another complex, float or int raise TypeError:
>
>>>> z = complex(0, 0)
>>>> z < int()
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
> TypeError: unorderable types: complex() < int()
>>>> z < float()
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
> TypeError: unorderable types: complex() < float()
>>>> z < complex()
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
> TypeError: unorderable types: complex() < complex()
>
> But Fraction is the odd man out:  a comparison between a Fraction and
> a complex raises a TypeError for complex numbers with nonzero
> imaginary component, but returns a boolean value if the complex number
> has zero imaginary component:
>
>>>> z < Fraction()
> False
>>>> complex(0, 1) < Fraction()
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
> TypeError: unorderable types: complex() < Fraction()
>
> I'm tempted to call this Fraction behaviour a bug, but maybe it arises
> from the numeric integration themes of PEP 3141.  Any ideas?

I'd call it a bug.

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[Python-Dev] Mixing float and Decimal -- thread reboot