how to remove repeating rows from a matrix?

2011 10 12
2 个回答
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0 个投票

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!

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Florin Neacsu
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
Zhang 2011-10-13
No, they are not always one after another.thx

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回答（2 个）

Andrei Bobrov
Andrei Bobrov 2011-10-12

1 个投票

unique(A,'rows')

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Zhang
Zhang 2011-10-13
Thx, Andrei, yes, it is more simple, but still out of memory in my real case

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Steven
Steven 2011-10-12

0 个投票

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

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Zhang
Zhang
2011-10-12

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