how to remove repeating rows from a matrix?

3 次查看（过去 30 天）

Zhang 2011-10-12

I know "union" can be used to achieve this, for example, there is an A,

A =

   2
   2
   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!

Florin Neacsu 2011-10-12

Hi,

Are your repeating lines always one after another? If so, you could use diff and look for [0 0].

Zhang 2011-10-13

No, they are not always one after another.thx

Andrei Bobrov 2011-10-12

unique(A,'rows')

Zhang 2011-10-13

Thx, Andrei, yes, it is more simple, but still out of memory in my real case

Steven 2011-10-12

Or even simpler for quick remove :

A(2,:)=[]

will give you B.

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