Fredrik Lundh wrote:
> "Cassiano, Marco" wrote:
>
>
>>I have difficulties with a weird Python 2.4.2 behaviour in comparing
>>Decimal to Floats.
>>
>>For Example :
>>
>>
>>
>>>>>from decimal import Decimal
>>>>>a=Decimal('3.7')
>>>>>b=6.3
>>
>>>>>if a > b :print a,b,'a is greater than b - NOT TRUE!!!!'
>>
>>... else: print a,b,'b is greater than a - CORRECT'
>>...
>>
>>
>>3.7 6.3 a is greater than b - NOT TRUE!!!!
>
>
> is this
>
> >>> 1.0 > "0"
> False
>
> also a bug ?
>
> http://www.python.org/doc/ref/comparisons.html
>
> "Most other types compare unequal unless they are the
> same object; the choice whether one object is considered
> smaller or larger than another one is made arbitrarily but
> consistently within one execution of a program."
It's not a bug, but it is a misfeature. In 3.0, I'd love to see
nonsensical comparisons raise TypeError, but still keep the ability to
sort lists of heterogeneous objects. One approach would be keep cmp(x,y)
permissive in its arguments while making __gt__ and friends strict.
Sorting would need to fall back __cmp__, if __lt__ either raised a type
error or returned a non int (e.g., numpy arrays). This could probably be
done by munging PyObject_RichCompareBool, but I haven't looked into it
in any detail.
My $0.02
-tim
[SNIP]
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