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Re: How to Sort/Uniq a list and keep its original index [message #50752 is a reply to message #50698]

Wed, 18 October 2006 11:36

Dilkushi@gmail.com
Messages: 21
Registered: August 2006

Junior Member

Thank you JD
this is waht i was looking for... perfect...
dilkushi

JD Smith wrote:

> On Wed, 11 Oct 2006 17:12:07 -0600, David Fanning wrote:
>>
>> I haven't tested this, but just off the top of my head:
>>
>> I = Where(Histogram(indexU, Min=0, Max=N_Elements(testTotal)) $
>> EQ 0, count)
>
> I think that will leave out one of the duplicates of each set (since
> one of them by definition is unique).
>
> If you're going to use HISTOGRAM, you could use it to do the whole
> thing:
>
> h=histogram(testTotal,REVERSE_INDICES=ri)
> wh=where(h gt 1,cnt) ;; bins with duplicates
> for i=0,cnt-1 do do_something_with,ri[ri[wh[i]]:ri[wh[i]+1]-1]
>
> since it's faster than SORT for well-behaved data. Notice that I didn't
> explicitly test for empty bins, since I'm only looping over those bins
> with 2 or more entries. If most of your duplicate counts are low (2x, 3x,
> etc.), you can see another big speedup by binning the resulting histogram.
> Standard sparse data warnings apply.
>
> If you want to use SORT anyway (for simplicity, or for instance
> because the data could be very sparse), your could just do the
> opposite of what UNIQ does:
>
> indexDUP=where((test eq shift(test,-1)) OR (test eq shift(test,1)))
>
> JD

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[Message index]

		Re: How to Sort/Uniq a list and keep its original index By: JD Smith on Thu, 12 October 2006 11:16
		Re: How to Sort/Uniq a list and keep its original index By: Jean H. on Thu, 12 October 2006 09:19
		Re: How to Sort/Uniq a list and keep its original index By: David Fanning on Wed, 11 October 2006 16:12
		Re: How to Sort/Uniq a list and keep its original index By: Dilkushi@gmail.com on Wed, 18 October 2006 11:36

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