title: How to restructure a pandas dataframe even in the presence of missing data
body: <p>If I had a pandas DataFrame which looks like this:</p>
  
  <pre><code>    df=pandas.DataFrame(range(8))
  
  
  
     0
  0  0
  1  1
  2  2
  3  3
  4  4
  5  5
  6  6
  7  7
  </code></pre>
  
  <p>What would be the best way to restructure this frame into two columns of five rows, regardless of the fact I only have 8 numbers? </p>
  
  <p>so the output would be :</p>
  
  <pre><code>   0  1
  0  0  5
  1  1  6 
  2  2  7
  3  3  NaN
  4  4  NaN
  5  5  NaN
  </code></pre>