How to remove rows having repeating elements from a matrix?

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If I have a matrix A=[ 1 2 1 4; 1 2 3 4; 3 2 1 4; 3 3 2 1] then I want a matrix as B=[ 1 2 3 4; 3 2 1 4] so that both the 1st and 4th row will be deleted as they have repeated elements. pls help me to find out the code.

Accepted Answer

Roger Stafford
Roger Stafford on 25 Apr 2016
Edited: Roger Stafford on 27 Apr 2016
t = false(1,size(A,1));
for k = 1:size(A,1)
u = unique(A(k,:));
t(k) = size(u,2)==size(A,2);
end
B = A(t,:); % Rows with repeated elements deleted

More Answers (1)

Baltam
Baltam on 25 Apr 2016
The below method is not elegant but it works.
A=[ 1 2 1 4; 1 2 3 4; 3 2 1 4; 3 3 2 1];
index = zeros(1,size(A,1));
for i = 1:size(A,1)
if numel(unique(A(i,:))) == numel(A(i,:))
index(i)=1;
end
end
index = logical(index);
B = A(index,:);
Kind regards,
Baltam
  2 Comments
David Wagener
David Wagener on 1 Dec 2019
The second version shown here while not as elegant works better if you have a large matrix and are using parallel processing. I'm not an expert by any means but the second version did not overload my machine like the first one did.

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