title: how to concatenate all rows of a column of a data frame in pandas without group by
body: <p>I have a dataframe like this</p>
  
  <p>Have been on it 12 days  along with 60 mg prozac 4+ years on that.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  index  sentences</p>
  
  <pre><code>  1   I feel the best I have felt in years.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
    2   "I have taken for over 7 years.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
    3   I slept 2 hours".                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
    4   IT SAVED MY LIFE                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
    5   IT SAVED MY LIFE" 
  </code></pre>
  
  <p>then I want to concatenate them in one array. the problem is that there maybe some sentences reptitive but still I want to keep all of them so the result will be:</p>
  
  <pre><code>["I feel the best I have felt in years", "I have taken for over 7 years." , "I slept 2 hours." , "IT SAVED MY LIFE" , "IT SAVED MY LIFE"]
  </code></pre>
  
  <p>I have tries this <a href="https://stackoverflow.com/questions/13944078/concatenate-rows-of-a-data-frame">link</a>  and <a href="https://stackoverflow.com/questions/44250019/how-to-concatenate-the-row-names-of-a-data-frame-with-a-special-character">this</a> which both are in r.</p>
  
  <p>I have also tried this approach:</p>
  
  <pre><code>dfsent.groupby(['sentences']).apply(','.join)
  </code></pre>
  
  <p>but as some of the rows in my data frame are repetitive it give me only one of them. in case of my example return me this:</p>
  
  <pre><code>["I feel the best I have felt in years", "I have taken for over 7 years." , "I slept 2 hours." , "IT SAVED MY LIFE" ]
  </code></pre>
  
  <p>Thanks in advance :)</p>