title: How to change a single value in a NumPy array?
body: <p>I want to change a single element of an array.
  For example, I have:</p>
  <pre><code>A = np.array([1,2,3,4],
               [5,6,7,8],
               [9,10,11,12],
               [13,14,15,16])
  </code></pre>
  <p>I want to relace <code>A[2][1] = 10</code> with <code>A[2][1] = 150</code>.
  How can I do it?</p>