MATLAB: How to set specific Elements of a Matrix to zero without a for loop

Question

Here is my problem:

o= ones(3,3) % Given Matrix
o =
       1     1     1
       1     1     1
       1     1     1
i = [1 2 2]; % column index of o, which should be set to zero
             % quantity of rows in o is always exactly the same like length(i)

The result after manipulating matrix o depending on i should be:

o =
       0     1     1
       1     0     1
       1     0     1

My simple solution

for k=1:length(i)
    o(k,i(k))=0;
end

How can i do that without a for loop. In fact, the number of rows of matrix o is 10 000.

Thank you very much!

Answer 1

o= ones(3,3);
ii = [1 2 2]; 
[m,n] = size(o);
o(sub2ind([m,n],(1:m)',ii(:)')) = 0;

other way

n = 3;
out = ~accumarray([(1:n)',ii(:)],1,[3,3]) + 0;