MATLAB: Reverse indexing with conditions

Question

Let A = [1 2 4 6 10], I want to find the indices of the matrix for which the element less than 5.

So if I say: A < 5, then it will return [1 1 1 0 0]. How can I proceed to get the index of all those 1's?

Thanks

Answer 1

idx = 1:numel(A);
mask = A < 5;
idx = idx(mask);