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Re: Efficient comparison of arrays [message #9700 is a reply to message #9699]

Sun, 10 August 1997 00:00

David R. Klassen
Messages: 14
Registered: December 1996

Junior Member

Andy Loughe wrote:
> Given vectors of the type...
>
> a = [1,2,3,4,5]
> b = [3,4,5,6,7]
>
> What is the most efficient way to determine which values that occur in
> a also occur in b (i.e., the values [3,4,5] occur in both a and b).
How about:
x=where(a eq b)
This will give you the index numbers in a of those values that are also in b.
So, to vector of the actual values would be a(x).

--
David R. Klassen
Department of Astronomy
Center for Radiophysics and Space Research
304 Space Sciences Building
Cornell University
Ithaca NY 14853
phone: 607-255-6910
http://faraday.uwyo.edu/grads/dklassen/
drk14@cornell.edu

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[Message index]

		Re: Efficient comparison of arrays By: wonko on Mon, 11 August 1997 00:00
		Re: Efficient comparison of arrays By: David P. Steele on Mon, 11 August 1997 00:00
		Re: Efficient comparison of arrays By: Struan Gray on Tue, 12 August 1997 00:00
		Re: Efficient comparison of arrays By: J.D. Smith on Mon, 11 August 1997 00:00
		Re: Efficient comparison of arrays By: Marty Ryba on Mon, 11 August 1997 00:00
		Re: Efficient comparison of arrays By: davidf on Sun, 10 August 1997 00:00
		Re: Efficient comparison of arrays By: David R. Klassen on Sun, 10 August 1997 00:00

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