title: How to unlist a list with one value inside a pandas columns?
body: <p>I have a pandas data frame:</p>
  <pre><code>Id       Col1
  1     ['string']
  2     ['string2']
  </code></pre>
  <p>Is possible to convert the data frame into another data frame that look like this?</p>
  <pre><code>Id     Col1
  1     string
  2     string2
  </code></pre>
  <p>I tried with this way but only get the <code>[</code>.</p>
  <pre><code>df.col1.apply(lambda x: x[0])
  </code></pre>
  <p>Thanks for your time!</p>