Re: where() and IEEE NaN

[davidf(at)dfanning.com (David Fanning)]

Todd Bowers (tbowers@nrlssc.navy.mil) writes:

> IDL> a = [1,2,!Values.F_NaN,4,!Values.F_NaN]
> IDL> print, a
>       1.00000      2.00000          NaN      4.00000          NaN
> IDL> print, where(a EQ !Values.F_NaN)
>            0           1           2           3           4
> 
> Hmmmmmm.... is this a known feature? 

Sure. Well known. :-)

I usually check for NANs like this:

   IDL> Print, Where( NOT Float( Finite(a) ) )    
        2      4 

Cheers,

David

-- 
David Fanning, Ph.D.
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