title: How to append all the columns into one column in Pandas?
body: <p>I'm trying to append the columns of a dataframe into one column via pandas library:</p>
  
  <p>DF is the table:<a href="https://i.stack.imgur.com/IGpg5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/IGpg5.png" alt="enter image description here"></a></p>
  
  <pre><code>oneCol = []
  colLength = len(finalDF)
  for k in range(colLength):
      oneCol.append(DF[k])
  combined = pd.DataFrame(oneCol)
  combined
  </code></pre>
  
  <p>but the output is <a href="https://i.stack.imgur.com/aqbsZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/aqbsZ.png" alt="enter image description here"></a></p>
  
  <p>what I'm after is just one column dataframe.
  Thank you.</p>