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Re: where() and IEEE NaN [message #17803 is a reply to message #17798]

Fri, 05 November 1999 00:00

Pavel Romashkin
Messages: 166
Registered: April 1999

Senior Member

I am not sure if trying to use WHERE on NaN is legitimate. NaN is a
missing value by definition, and the request to WHERE those values is
senseless. However, I'd too better like WHERE to complain than to
quietly return some array.

It does not seem to be a *practical* problem because NaNs don't sneak
into your arrays unless you place them in. And if you do, then handle
them accordingly.

As for whether its right or wrong, I think someone said it before: iI am
more interested in how to do what I need, not in how I think they did it
wrong.

Cheers,
Pavel

Todd Bowers wrote:

> 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? The where() help says
> nothin' about NaN's.
> IDL v5.2a
>
> Thanks
> Todd

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[Message index]

		Re: where() and IEEE NaN By: korpela on Mon, 08 November 1999 00:00
		Re: where() and IEEE NaN By: badastro on Mon, 08 November 1999 00:00
		Re: where() and IEEE NaN By: Pavel Romashkin on Mon, 08 November 1999 00:00
		Re: where() and IEEE NaN By: thompson on Mon, 08 November 1999 00:00
		Re: where() and IEEE NaN By: jsb on Thu, 11 November 1999 00:00
		Re: where() and IEEE NaN By: korpela on Sat, 06 November 1999 00:00
		Re: where() and IEEE NaN By: Vincenzo Andretta on Sat, 06 November 1999 00:00
		Re: where() and IEEE NaN By: davidf on Fri, 05 November 1999 00:00
		Re: where() and IEEE NaN By: davidf on Fri, 05 November 1999 00:00
		Re: where() and IEEE NaN By: Pavel Romashkin on Fri, 05 November 1999 00:00
		Re: where() and IEEE NaN By: thompson on Fri, 05 November 1999 00:00
		Re: where() and IEEE NaN By: T Bowers on Fri, 05 November 1999 00:00
		Re: where() and IEEE NaN By: badastro on Fri, 05 November 1999 00:00
		Re: where() and IEEE NaN By: davidf on Fri, 05 November 1999 00:00
		Re: where() and IEEE NaN By: korpela on Fri, 05 November 1999 00:00

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