MRAB wrote:
Here's a curiosity. float("nan") can occur multiple times in a set or as
a key in a dict:
>>> {float("nan"), float("nan")}
{nan, nan}
except that sometimes it can't:
>>> nan = float("nan")
>>> {nan, nan}
{nan}
It's fundamentally because NaN is not equal to itself, by design.
Dictionaries and sets rely on equality to test for uniqueness of keys or
elements.
>>> nan = float("nan")
>>> nan == nan
False
In short, don't do that.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
There was never a good war or a bad peace.
-- Benjamin Franklin, 1706-1790
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