title: Accessing every 1st element of Pandas DataFrame column containing lists
body: <p>I have a Pandas DataFrame with a column containing lists objects</p>
  
  <pre><code>      A
  0   [1,2]
  1   [3,4]
  2   [8,9] 
  3   [2,6]
  </code></pre>
  
  <p>How can I access the first element of each list and save it into a new column of the DataFrame? To get a result like this:</p>
  
  <pre><code>      A     new_col
  0   [1,2]      1
  1   [3,4]      3
  2   [8,9]      8
  3   [2,6]      2
  </code></pre>
  
  <p>I know this could be done via iterating over each row, but is there any "pythonic" way? </p>