how can i find identical rows in a matrix

I have a 158x7 matrix. I want to find if there is at least one row which is identical.

[Geoff Hayes]

AA - please describe what you mean by similar. Do you meant that the two rows are identical or share the same values or share a pattern of numbers? Be clear about what the problem is you are trying to solve. Use the question body to include more than just a repeat of your question header.

[AA]

ok i changed the question. thanks for the advice

Answer 1

[Konstantinos Sofos]

Use unique() to find the distinct row values. If you end up with fewer rows, there are duplicates. It'll also give you indexes of one location of each of the distinct values. All the other row indexes are your duplicates.

x = [
    1 1
    2 2
    3 3
    4 4
    2 2
    3 3
    3 3
    ];
[u,I,J] = unique(x, 'rows', 'first')
hasDuplicates = size(u,1) < size(x,1)
ixDupRows = setdiff(1:size(x,1), I)
dupRowValues = x(ixDupRows,:)

Answer 2

[Star Strider]

Use the unique function with the 'rows' option.

[AA]

would it be possible to give me an example?

[AA]

B = unique(A,'rows');

As a check, if size(B) ~= size(A), then you have at least two identical rows.