Message233737
| Author |
vstinner |
| Recipients |
ethan.furman, mark.dickinson, pitrou, serhiy.storchaka, vstinner |
| Date |
2015年01月09日.08:57:15 |
| SpamBayes Score |
-1.0 |
| Marked as misclassified |
Yes |
| Message-id |
<1420793836.41.0.0549154776279.issue23185@psf.upfronthosting.co.za> |
| In-reply-to |
| Content |
2015年01月09日 8:16 GMT+01:00 Serhiy Storchaka <report@bugs.python.org>:
> May be make math.inf and math.nan special objects so that for all x (except inf and nan):
What do you mean? Implement a subtype of float and override some methods?
> x < math.inf
> x > -math.inf
It's already the case for int, float and decimal.Decimal.
> not (x < math.nan)
> not (x > math.nan)
Comparison to nan always return False.
I would be better to raise an error when nan is compared to other numbers (I mean operations like a>b, not a==b), but Python was not designed like that (nor the IEEE 754?).
>>> sorted((nan, 1, nan, 2))
[nan, 1, nan, 2]
Sorting with NaN is a common issue :-/ See for example:
https://stackoverflow.com/questions/4240050/python-sort-function-breaks-in-the-presence-of-nan
Anyway, changing NaN behaviour is out of the scope of this issue! |
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