title: How to remove a column in a numpy array?
body: <p>Imagine we have a 5x4 matrix. 
  We need to remove only the first dimension. 
  How can we do it with <strong>numpy</strong>? </p>
  
  <pre><code>array([[  0.,   1.,   2.,   3.],
         [  4.,   5.,   6.,   7.],
         [  8.,   9.,  10.,  11.],
         [ 12.,  13.,  14.,  15.],
         [ 16.,  17.,  18.,  19.]], dtype=float32)
  </code></pre>
  
  <p>I tried:</p>
  
  <pre><code>arr = np.arange(20, dtype=np.float32)
  matrix = arr.reshape(5, 4)
  new_arr = numpy.delete(matrix, matrix[:,0])
  trimmed_matrix = new_arr.reshape(5, 3)
  </code></pre>
  
  <p>It looks a bit clunky. 
  Am I doing it correctly?
  If yes, is there a cleaner way to remove the dimension without reshaping? </p>