"/a" is not "/a" ?

[Lie Ryan]

Robert Kern wrote:
> On 2009-03-07 08:14, Christian Heimes wrote:
>> Steven D'Aprano wrote:
>>> Yes. Floating point NANs are required to compare unequal to all floats,
>>> including themselves. It's part of the IEEE standard.
>>
>> As far as I remember that's not correct. It's just the way C has
>> interpreted the standard and Python inherited the behavior. But you may
>> proof me wrong on that.
>>
>> Mark, you are the expert on IEEE 754.
> 
> Steven is correct. The standard defines how boolean comparisons like ==, 
> !=, <, etc. should behave in the presence of NaNs. Table 4 on page 9, to 
> be precise.
> 

The rationale behind the standard was because NaN can be returned by 
many distinct operations, thus one NaN may not be equal to other NaN.