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Re: findng array[3] in array[3,n] [message #23513 is a reply to message #23510]

Thu, 25 January 2001 09:24

John-David T. Smith is currently offline

John-David T. Smith
Messages: 384
Registered: January 2000

Senior Member

tbowers wrote:
>
> If I have
>
> a=[ $
> [0,1,2], $
> [3,4,5], $
> [6,7,8]]
>
> b=[3,4,5]
>
> how do I find where in a is the row vector b? The answer should
> be 1, the 2nd row of a. I've tried many
> permutations of where(), but I just don't get it. The only way I
> can get an answer is to loop through the rows till i find a match.
> What I'm really tryin' to do is to find a color in a color table,
> e.g. load RAINBOW color table, (loadct,13) then identify
> where a color is. For the color that's listed 6th in the color table
> (an almost black) that'd be the 5th row index. Like:

> So, does anyone know see an elegant solution to this problem??

I can't say it's elegant, but:

where(total(rebin(b,n_elements(b),(size(a,/DIMENSIONS))[1],/ SAMP) eq
a,1) eq n_elements(b))

The rule is, when comparing arrays, you must expand the smaller to the
size of the larger.

JD

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[Message index]

		Re: findng array[3] in array[3,n] By: Craig Markwardt on Fri, 26 January 2001 05:42
		Re: findng array[3] in array[3,n] By: T Bowers on Thu, 25 January 2001 14:53
		Re: findng array[3] in array[3,n] By: davidf on Thu, 25 January 2001 09:48
		Re: findng array[3] in array[3,n] By: Craig Markwardt on Thu, 25 January 2001 09:30
		Re: findng array[3] in array[3,n] By: davidf on Thu, 25 January 2001 09:31
		Re: findng array[3] in array[3,n] By: John-David T. Smith on Thu, 25 January 2001 09:24

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