MATLAB: How to assign values to a matrix from index array

Question

I have an initial zeros matrix A, to fill with ones at matrix coordinates given by elements in x and y. but when i do A(x,y)=1, it does not work.

I have this:

when I do A(x,y)=1, I got this:

but I expect this:

How should I do this assignment?

Thanks.

Answer 1

A(sub2ind(size(A),x,y)) = 1;