Finding rows in a matrix

I have a matrix A = [1 2; 2 1; 1 2; 2 2; 1 1; 2 2]

I want to count how many times the row [1 2] appears in above matrix A. Here for my counting purpose [1 2] would appear 3 times as [1 2] or [2 1].

Thanks guys

Answer 1

[Matt Fig]

Another:

% The given matrix
A = [1 2; 2 1; 1 2; 2 2; 1 1; 2 2];

% Now find the counts.
[I,J,K] = unique(sort(A,2),'rows'); % I has the unique rows.
C = histc(K,1:max(K));  % This has the corresponding counts.

% Now that we have found the counts, display them:
fprintf('Row [%i %i] appears %i times. \n',[I C]')

If you want to only get the counts for the one type, this will do it quickly:

cnt = sum(all(bsxfun(@eq,sort(A,2),[1,2]),2));

Answer 2

[Azzi Abdelmalek]

A = randi(2,10,2)
idx=find(any(repmat([1 2],size(A,1),1)-sort(A,2),2)==0)

Answer 3

[Image Analyst]

Here's a brute force approach:

A = [1 2; 2 1; 1 2; 2 2; 1 1; 2 2]
sortedA = sort(A, 2)
uniqueRows = unique(sortedA, 'rows')
counts = zeros(1, size(uniqueRows, 1)); % Preallocate.
for row = 1 : size(uniqueRows, 1)
  for rowA = 1 : size(A, 1)
    matches = sortedA(rowA, :) == uniqueRows(row, :);
    if all(matches)
      counts(row) = counts(row) + 1;
    end
  end
end
counts

In the command window:

A =
     1     2
     2     1
     1     2
     2     2
     1     1
     2     2
sortedA =
     1     2
     1     2
     1     2
     2     2
     1     1
     2     2
uniqueRows =
     1     1
     1     2
     2     2
counts =
     1     3     2