title: Numpy 2d array, select indices satisfying conditions from 2 arrays
body: <p>I have two 3x3 arrays. One of them indicates if an element is black (let's say 0's - white, 1's black) and another what is the cost of an element. Is there a nice way to get indices of for example all elements that are black and their price is higher than certain value? I know I can use np.where() to select from one array, but how to do it on two (if they have the same shapes)</p>