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histogram & reverse_indices [message #30071]

Tue, 09 April 2002 12:15

Ken Mankoff
Messages: 158
Registered: February 2000

Senior Member

Hi,

As you may have guessed from the subject, I have a question about
histogram and reverse indices...

I have a 2D array made up of n quadruplets. Ex:
array =[[1,1,1,2], $
[1,1,1,1], $
[3,4,3,2], $
[3,3,0,0], $
[5,5,0,5]]

I want my algorithm to do the following: Return the index of all the
quadruplets that have at least 3 out of 4 numbers equal to each other
(i.e. for the above array, it should return [0,1,4].

I can do it in a for-loop as follows:

for i=0,n_elements(array[0,*])-1 do begin
quad = array[*,i]
hist = histogram( quad )
hist = hist[ where( hist ne 0 ) ]
if ( max( hist ) gt 3 then print, 'good' else print, 'bad'
endfor

But I think there is a way to do this without a for loop. Either using
reverse_indices, or where(), I just cannot see it. Can you?

-k.

--
Kenneth Mankoff
LASP://303.492.3264
http://lasp.colorado.edu/~mankoff/
http://lasp.colorado.edu/snoe/
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[Message index]

		histogram & reverse_indices By: Ken Mankoff on Tue, 09 April 2002 12:15
		Re: histogram & reverse_indices By: Ken Mankoff on Wed, 10 April 2002 07:26
		Re: histogram & reverse_indices By: the_cacc on Wed, 10 April 2002 03:02
		Re: histogram & reverse_indices By: Craig Markwardt on Tue, 09 April 2002 19:35
		Re: histogram & reverse_indices By: Wayne Landsman on Tue, 09 April 2002 13:47

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