title: Numpy set all indexes to a value
body: <p>I have a numpy ndarray <code>a = np.ndarray((3,3))</code> and I want all of the indexes to start at the same value, e.g. 5:</p>
  
  <pre><code>array([[5., 5., 5.],
         [5., 5., 5.],
         [5., 5., 5.]])
  </code></pre>
  
  <p>Note: I'm posting this Q&amp;A style because every time I look this up I always find a bunch of random questions about complex slicing, but not a simple example of casting everything at once.  Hopefully this will pop up as a more immediate result next time I search this question.
  But I also hope that others have good ideas I can adopt.</p>