Counting the number of the unique value in each row of a matrix without using for loop

M = randi(21,[1000000,9]);
counter = zeros(size(A,1),1);
for j = 1 : size(A,1)    
    a = unique(Mat(j,:));
    counter(j) = numel(a);    
end

Hi

I have big size matrix (M in the above code) and I want to count the number of the unique value in each row.

I do not need the values and only the number of unique value is important to me.

The above for loop is a part of my program that needs to be repeated more and more times.

Because of the size of M, it is very time consuming and i dont want to use the above for loop.

Is there a faster alternative?

Thanks

[Iuliu Ardelean]

https://stackoverflow.com/questions/36970733/how-to-find-number-of-unique-elements-in-each-row-of-a-matrix

Your solution takes 10.6 seconds for me. One of the solutions in link above took 0.44 seconds.

[Stephen23]

The reason why I gave up on Stack Exchange was because of too much incorrect information or very poor understanding of how to use MATLAB effectively. This thread is a good example, when the most popular answer starts with the remarkably narrow-minded "You need to use unique function on each row...".

Answer 1

[Stephen23]

M = randi(9,5,7)

M = 5×7

5 4 8 4 9 6 9 3 2 5 9 8 1 8 4 4 8 7 3 3 1 6 7 4 6 6 3 1 6 3 4 2 5 9 7

N = 1+sum(diff(sort(M,2),1,2)~=0,2)

N = 5×1

5 6 5 5 7

[reza aghaee]

Very cleverly

Thanke you so much

[Stephen23]

@reza aghaee: please remember to accept my answer if it helped you!