how to remove repeating rows from a matrix?

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!

[Florin Neacsu]

Hi,

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

[Zhang]

No, they are not always one after another.thx

Answer 1

[Andrei Bobrov]

unique(A,'rows')

[Zhang]

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

Answer 2

[Steven]

Or even simpler for quick remove :

A(2,:)=[]

will give you B.