title: Python: numpy data type casting
body: <p>I'm confused by some output I'm seeing.</p>
  
  <p>If p is a list of floats, what is the difference between:</p>
  
  <pre><code>input = np.array([p]).astype('f')
  </code></pre>
  
  <p>and</p>
  
  <pre><code>input = np.array([p],float)
  </code></pre>
  
  <p>If I use the second option and then do a print(input), I always get something like:</p>
  
  <p>[array([-0.662,  0.246,  1.029])]</p>
  
  <p>But if I use the first option, sometimes I get simply:
  [[ 0.61900002  1.71300006  2.16899991]] </p>
  
  <p>but other times I get the [array([])] form.</p>