how to remove repeating rows from a matrix?

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Zhang
Zhang on 12 Oct 2011
I know "union" can be used to achieve this, for example, there is an A,
A =
1 2
1 2
1 3
B=union(a,a,'rows')
B =
1 2
1 3
but if A is big(In my case, A is a 20,000*30 matrix), it will be out of memory.
??? Out of memory. Type HELP MEMORY for your options.
ARE there simple ways to delete repeating arrows in a matrix? THX!
  2 Comments
Florin Neacsu
Florin Neacsu on 12 Oct 2011
Hi,
Are your repeating lines always one after another? If so, you could use diff and look for [0 0].
Zhang
Zhang on 13 Oct 2011
No, they are not always one after another.thx

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Answers (2)

Andrei Bobrov
Andrei Bobrov on 12 Oct 2011
unique(A,'rows')
  1 Comment
Zhang
Zhang on 13 Oct 2011
Thx, Andrei, yes, it is more simple, but still out of memory in my real case

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Steven
Steven on 12 Oct 2011
Or even simpler for quick remove :
A(2,:)=[]
will give you B.

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