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Re: Clever Where() test [message #4379 is a reply to message #4370]

Thu, 25 May 1995 00:00

bertin
Messages: 4
Registered: October 1994

Junior Member

Andy Loughe (afl@cdc.noaa.gov) wrote:
> In article <moleD93CEG.79n@netcom.com>, mole@netcom.com (Aaron Birenboim) writes:
> |> Is there a clever way to test for null return (-1) from WHERE???
> |>
> |> I'm doing stuff like :
> |>
> |> i = WHERE(x GT 0.0)
> |> s = SIZE(i)
> |> IF s(0) EQ 0 THEN BEGIN
> |> IF i GE 0 THEN BEGIN
> |> ; do something with x(i)
> |> ENDIF
> |> ENDIF ELSE BEGIN
> |> ; do something with the multiple elements x(i)
> |> ENDIF
> |>
> |> Is there a more clever way to handle this? Especially since the
> |> "do something...." code is often the same weather i is scalar or vector.
> |>
> |> I wish that "IF i eq -1 THEN..." wouldnt crash for vector i's!!!
> |> --
>
>
> How about this?
>
> i = WHERE( x GT 0.0, count)
> IF ( count gt 0 ) then 'do something with the x's
>
> The count is very handy indeed. You could also build a
> loop from 0, count-1 if you needed to.
>
> --

or this

IF i(0) EQ -1 THEN ...

Works for vector and scalar i's

Scott J. Bertin
bertin@euler.cpi.com

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[Message index]

		Re: Clever Where() test By: steinhh on Fri, 26 May 1995 00:00
		Re: Clever Where() test By: thompson on Thu, 25 May 1995 00:00
		Re: Clever Where() test By: Paul Probert on Thu, 25 May 1995 00:00
		Re: Clever Where() test By: thompson on Thu, 25 May 1995 00:00
		Re: Clever Where() test By: bertin on Thu, 25 May 1995 00:00
		Re: Clever Where() test By: afl on Wed, 24 May 1995 00:00
		Re: Clever Where() test By: offenbrg on Tue, 30 May 1995 00:00
		Re: Clever Where() test By: thompson on Tue, 30 May 1995 00:00

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