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Re: remove duplicates WITHOUT sorting [message #52570 is a reply to message #52568]

Mon, 12 February 2007 09:23

Vince Hradil
Messages: 574
Registered: December 1999

Senior Member

On Feb 12, 11:04 am, "rpert...@gmail.com" <rpert...@gmail.com> wrote:
> Hello All,
> I have an array of 2xn which is a list of coordinates (x,y positions)
> and I need to remove any duplicates in this array. Since they are x,y
> coordinates I cannot really sort the array, hence cannot use the Uniq
> function. Is there another way of doing this?
> My array is similar to:
> [2 30
> 4 5
> 3 9
> 51 19
> 12 15
> 3 9
> 11 22
> 32 33
> 14 25]
>
> As you see index 4,5 is same as index 10,11. How do i rewrite this
> array without duplicates? Is there a general way of doing this, as
> some of my coordinates (to make matters even more complicated) are not
> exactly the same, but are close (3,9) and (3.5,9) - But I think I can
> figure this out with some if...then statements. Not sure how to remove
> them though. Any help is appreciated!
> Thank you,
> Radha

How about this:

function uniq_coords, coords
cc = complex( reform(coords[0,*]), reform(coords[1,*]) )
cc = cc[uniq(cc,sort(cc))]
cc = transpose( [ [float(cc)],[imaginary(cc)] ] )
return, cc

Of course this will make the return value floats, but you can fix that
up to handle other types if you want.
Also, I have no idea how well this will perform - time to execute,
robustness, etc - just seemed to work on your test array. "caveat
emptor"

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[Message index]

		Re: remove duplicates WITHOUT sorting By: Jean H. on Tue, 13 February 2007 08:10
		Re: remove duplicates WITHOUT sorting By: rpertaub@gmail.com on Tue, 13 February 2007 07:18
		Re: remove duplicates WITHOUT sorting By: JD Smith on Mon, 12 February 2007 13:15
		Re: remove duplicates WITHOUT sorting By: btt on Mon, 12 February 2007 11:23
		Re: remove duplicates WITHOUT sorting By: Brian Larsen on Mon, 12 February 2007 10:38
		Re: remove duplicates WITHOUT sorting By: David Fanning on Mon, 12 February 2007 09:38
		Re: remove duplicates WITHOUT sorting By: Vince Hradil on Mon, 12 February 2007 09:23
		Re: remove duplicates WITHOUT sorting By: Craig Markwardt on Mon, 12 February 2007 09:23
		Re: remove duplicates WITHOUT sorting By: Vince Hradil on Wed, 14 February 2007 07:32

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