Extract a row from a 2D matrix if any of its element matches with elements in other 1D matrix

I have 2D matrxi A (size: 10000 x 3) and 1D matrix B (size: 5000 x 1)

If one elemnt of row in A matches with any element in B, then that rwo sfould be separated out. Suppose there are N such rows then I want the output as a matrix C (size: N x 3), (which is a subset of A).

I am using the code:

counter = 0

for i = 1:length(A)

if sum(ismember(A(i,:),B)) >= 1

counter = counter + 1;

C(counter,:) = A(i,:);

end

end

This gives me the output I want, but it takes huge time especially on very large sized matrices.

Any one/two liner replacment to speed up the code?

Thanks.

[Gifari Zulkarnaen]

Thanks for the ismember tho, I just known it.

[Sachin Shinde]

Thanks

Answer 1

[Gaurav Aggarwal]

Hi Sachin,

Can you check if this works for you?

C = A(any(ismember(A,B),2),:);

Thanks.

[Sachin Shinde]

This works perfectly, and quite fast!

Thank you very much.

Answer 2

[Gifari Zulkarnaen]

Try this:

idx = [];
for i = 1:size(A,1)
    if any(ismember(A(i,:),B))
        idx = [idx i];
    end
end
C = A(idx,:);

[Sachin Shinde]

This works, but takes nearly the same time!