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Re: Clever Where() test [message #4436 is a reply to message #4386]

Tue, 30 May 1995 00:00

offenbrg
Messages: 31
Registered: August 1993

Member

afl@cdc.noaa.gov (Andy Loughe) writes:

> 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!!!
> |> --

There's another cute way:

i = WHERE(x GT 0.0)
IF (i(0) ge 0) THEN BEGIN
blah blah
endIF

If "I" is a scalar, "I(0)" will still equal "I".

Joel

--
"...And I am unanimous in this." - Mrs. Slocumbe
Joel D. Offenberg | offenbrg@fondue.gsfc.nasa.gov
Hughes STX, NASA/GSFC/LASP | (301)-286-5801

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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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