title: How do you join multiple rows into one row in pandas?
body: <p>I have a list that I'm trying to add to a dataframe. It looks something like this:</p>
  <pre><code>list_one = ['apple','banana','cherry',' ', 'grape', 'orange', 'pineapple','']
  </code></pre>
  <p>If I add the list to a dataframe, using <code>df = pd.DataFrame({'list_one':list_one})</code> it'll look like this:</p>
  <pre><code>       list_one
     -------------
     0   apple
     1   banana 
     2   cherry
     3  
     4   grape
     5   orange
     6   pineapple
     7  
  </code></pre>
  <p>I want the combine some of the rows into one row, so that the dataframe looks something like this:</p>
  <pre><code>       list_one
     -----------------------------
     0   apple, banana, cherry 
     1   grape, orange, pineapple
  </code></pre>
  <p>Is there a simple way to do this?</p>
  <p>Thank you for taking the time to read my question and help in any way you can.</p>