title: Why dataframe.shape[0] prints an integer, but dataframe.columnname.shape prints a tuple
body: <p>Just curious.</p>
  
  <p>I have some data I am working with, and when I input</p>
  
  <pre><code>train.Id.shape
  </code></pre>
  
  <p>python returned <code>(1467,)</code> - a tuple</p>
  
  <p>but when I input </p>
  
  <pre><code>train.shape[0]
  </code></pre>
  
  <p>python returned <code>1467</code> - an integer</p>
  
  <p>Curious how Pandas handles these two different inputs, and why they are different.
  Is this a specific feature, or just a quirk?</p>