find the repetition of matrix rows

4 views (last 30 days)
I want to find out if the row i of mxn matrix is repeated ,the code should give logic 1.Otherwise zero"there are many ways but Im searching for the best one" Thanks
  2 Comments
Cedric
Cedric on 7 May 2014
Please provide an example.
José-Luis
José-Luis on 7 May 2014
And please instead of asking an almost repeated question, try to explain better what you want, and please show some effort before asking for a ready-made answer.

Sign in to comment.

Accepted Answer

Roberto
Roberto on 9 May 2014
Edited: Roberto on 9 May 2014
a = [1 2 3; 4 5 6;1 2 3; 3 2 4; 1 2 3; 3 2 1; 1 3 2] ;
row2check = 1;
repeated = 0 ;
for i = 1 : size(a,1)
repeated = repeated + prod(double([a(row2check,:)== a(i,:)])) ;
end
fprintf('\n Row number %i is reapeated %i times in matrix!\n\n',row2check,repeated);

More Answers (1)

Image Analyst
Image Analyst on 9 May 2014
Edited: Image Analyst on 9 May 2014
Using ismember() is the usual method. Try this:
m = randi(9, [5000, 3]); % Create sample data.
% For demo, let's make sure row 9 is a repeat.
% In other words, row 9 is a duplicate of row 1.
m(9,:) = m(1,:);
% Let's see if row i is repeated
i = 1; % Could be any number up to size(m, 1);
% Use ismember to find repeated rows.
[lia, locb] = ismember(m, m(i,:), 'rows');
% locb is a logival vector. Find the actual row numbers.
repeatedRows = find(locb)

Categories

Find more on MATLAB in Help Center and File Exchange

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!