title: numpy: syntax/idiom to cast (n,) array to a (n, 1) array?
body: <p>I'd like to cast a numpy <code>ndarray</code> object of shape (<em>n</em>,) into one having shape (<em>n</em>, 1).  The best I've come up with is to roll my own _to_col function:</p>
  
  <pre><code>def _to_col(a):
      return a.reshape((a.size, 1))
  </code></pre>
  
  <p>But it is hard for me to believe that such a ubiquitous operation is not already built into numpy's syntax.  I figure that I just have not been able to hit upon the right Google search to find it.</p>