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Student Support Forum: 'DeleteDuplicates' topicStudent Support Forum > General > Archives > "DeleteDuplicates"

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Denis
09/20/10 12:09pm

Hi! Sorry for my bad English.
I'd like to delete duplicates in such list:
{ {{1,2},{2,1}}, {{2,1},{1,2}} }. It's about sets of integer 2D points, so {{x1,y1},{x2,y2}}
is the same that {{x2,y2},{x1,y1}}, but DeleteDuplicates[] don't recognize it. @, @@ and more tricky things not work. "Simple" solution is:
DeleteDuplicates@Sort/@someList;
but Sort is very slow function for big and nested arrays. I'm interesting some chess combinatorics problem and Timing[] show, that without Sort[] all will be 100-200 times faster. Please maybe someone
can tell me how change DeleteDuplicates attributes
or another thing that help to avoid Sort??

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Subject (listing for 'DeleteDuplicates')
Author Date Posted
DeleteDuplicates Denis 09/20/10 12:09pm
Re: DeleteDuplicates TomD 09/21/10 06:49am
Re: DeleteDuplicates Daniel Z-S 09/21/10 09:39am
Re: DeleteDuplicates lesobrod 09/22/10 12:53pm
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