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Re: Finding the index of the median [message #7258 is a reply to message #7252]

Tue, 29 October 1996 00:00

davidf
Messages: 2866
Registered: September 1996

Senior Member

Dean Schulze <schulze@cassini.lpl.arizona.edu> writes:

> The median function will return the median value of an
> array. Is there anyway to obtain the index into the array
> of the median value? For example, if I find the median in an
> array of measured values how can I get the corresponding value
> from the companion noise array?

The easiest way is to use the WHERE function. Your code might
look something like this:

array = [3, 7, 2, 8, 15, 1]
noise = RANDOMU(seed, 6)

medianValue = MEDIAN(array)
index = WHERE(array EQ medianValue)

Print, noise(index)

Be aware that there can be multiple locations in your
array that are equal to the median value. The index that
is returned by the WHERE function will be an array of
all of those values.

Just a tip. The return value from the WHERE funcution
(if it finds something) is *always* an array, even if it
finds only one instance. If you are going to use that
return value as if it were a scalar value (e.g., as a counter
in a loop) be sure you subset it like this: index(0).

Yours,

David

--
David Fanning, Ph.D.
Phone: 970-221-0438
Fax: 970-221-4728
E-Mail: davidf@fortnet.org

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[Message index]

		Re: Finding the index of the median By: davidf on Tue, 29 October 1996 00:00
		Re: Finding the index of the median By: Dean Schulze on Tue, 29 October 1996 00:00
		Re: Finding the index of the median By: peter on Tue, 29 October 1996 00:00
		Re: Finding the index of the median By: Joseph M Zawodny on Tue, 29 October 1996 00:00
		Re: Finding the index of the median By: Joseph M Zawodny on Tue, 29 October 1996 00:00
		Re: Finding the index of the median By: davidf on Tue, 29 October 1996 00:00

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