[Python-ideas] math.inf and math.nan constants

Ethan Furman ethan at stoneleaf.us
Wed Jan 7 20:49:37 CET 2015


On 01/07/2015 11:02 AM, Bruce Leban wrote:
> 
> There is a problem here but that's not it. The problem is that 
> 
>     float("nan") is float("nan") => False
>     math.nan is math.nan => True

This is not a new problem:

    --> nan = float('nan')
    --> nan is nan
    True

> So is this an attractive nuisance that will make people think they can should use x is math.nan instead of
> math.isnan(x)? Hopefully not but something to consider. Pylint should flag this usage.

Agreed, for all linters.

--
~Ethan~

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