title: Is there way to un-nest a list column in a pandas dataframe?
body: <p>I have pandas dataframe with a list as one of the columns. I want to expand that list out into 4 separate columns.</p>
  <pre><code>df=pd.DataFrame({'A':[1,2],'B':[[1,2,3,4],[1,2,5,8]]})
  df
  Out[458]: 
     A  B
  0  1  [1, 2, 3, 4]
  1  2  [1, 2, 5, 8]
  </code></pre>
  <p>I'd like this to be:</p>
  <pre><code>   A  C_1  C_2  C_3 C_4
  0  1  1    2    3   4
  1  2  1    2    5   8
  </code></pre>