test for nan

[Roel Schroeven]

Skip Montanaro wrote:
>     John> Is there a better way to test for NaN than
> 
>     John>    str(p1)=='nan'
> 
>     John> where p1 is a float?
> 
> Saw this in the list archives earlier today:
> 
>     >>> inf = float("1e9999")
>     >>> inf
>     Inf
>     >>> nan = inf-inf
>     >>> nan
>     NaN
>     >>> p1 = 5.0
>     >>> p1 == nan
>     False

 >>> a = inf-inf
 >>> a == nan
False

Seems to return False always, that doesn't really help...

-- 
"Codito ergo sum"
Roel Schroeven