identify duplicate rows in a matrix

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Ananya Malik
Ananya Malik on 6 Oct 2016
Answered: KSSV on 6 Oct 2016
I have a matrix
A = [1 2 3; 3 4 5; 1 2 3];
I want to identify the duplicate row i.e. 3rd row and replace the values in that row by 0.
Resultant A = [1 2 3; 3 4 5; 0 0 0];
Is there an efficient way to do this? Thanks in Advance.

Accepted Answer

Massimo Zanetti
Massimo Zanetti on 6 Oct 2016
You can identify the repeated rows by invoking unique function of Matlab, and then set to 0 non-unique rows as follows:
[C,ia,ib]=unique(A,'rows','stable');
i=true(size(A,1),1);
i(ia)=false;
A(i,:)=0;
Then A will be your output.

More Answers (1)

KSSV
KSSV on 6 Oct 2016
A = [1 2 3; 3 4 5; 1 2 3];
[C,ia,ic] = unique(A,'rows') ;
iwant = zeros(size(A)) ;
iwant(ia,:) = C ;

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