title: Change pandas series type from str to list/numeric
body: <p>I have the following dataframe:</p>
  <p><code>df_small</code>
  <a href="https://i.stack.imgur.com/dIm2s.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dIm2s.png" alt="enter image description here" /></a></p>
  <p>Each column is of type <code>pandas.Series</code> and each value inside a column is of type <code>str</code>.</p>
  <pre class="lang-py prettyprint-override"><code>df_small['center'][0] # '[(181, 186)]'
  </code></pre>
  <p>I want to remove the string quotations from each value to access the list values.</p>