This can probably be optimized, but it works to replace rows that don't occur more times than the set threshold, in this case 3 times.
M = [9 10; 9 10; 9 10; 9 10; 9 10; 7 12; 3 4; 3 4; 3 4; 3 4; 7 12];
threshold = 3;
[~, ~, ic] = unique(M, 'rows', 'stable');
numOccurances = accumarray(ic, 1);
idxToDelete = false(size(M,1), 1);
for i = 1:length(numOccurances)
if numOccurances(i) < threshold
duplicateRows = find(ic==i);
idxToDelete(duplicateRows) = true;
end
end
M(idxToDelete,:) = 0;
If you want to delete the rows entirely, you can replace the last line with this:
M(idxToDelete,:) = []; % Alternatively, delete rows
