unique rows of matrix

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xplore29 2013-3-25

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https://ww2.mathworks.cn/matlabcentral/answers/68604-unique-rows-of-matrix

采纳的回答： Matt Kindig

I have to create new matrix A from a given matrix B in the following manner

B=[1 4 2;1 5 2;1 5 2;3 3 4;3 1 4;2 1 3;2 6 3]

A=[1 2;3 4;2 3]

i-e in forming A we ignore the values which 2nd column takes in and considers only column 1 and 3 create A.

unique(A,'rows') will not do the job . Do I have to create an intermediate matrix from column 1 and 3 and the apply this unique function to get the desired matrix or is there any other option available which avoids formulation of intermediate matrix

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Answer 1

Matt Kindig 2013-3-25

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You can easily perform the task using:

A = unique( B(:,[1 3]), 'rows');

But of course, this forms the intermediate matrix to run the unique() function. Is there a particular reason you need to avoid this intermediate matrix running (memory issues, perhaps)?