title: How can I add list side by side (not by using append)?
body: <p>I need to add lists in side ways, not in the below. So I think 'append()' is not appropriate. 'concat()' seems to be adding in side ways, but not working for lists. </p>
  
  <p>Do I need to use concat() to add list side ways? If so, how can I do that with lists?  </p>
  
  <pre><code>months = range(1,3)
  
  pieces=[]
  columns = ['id','q1','q2','q3']
  
  for month in months:
      path = 'C:/Users/uib57309/Desktop/newfolder/01_Survey/month/%d.csv' %month
      frame = pd.read_csv(path, names = columns)
  
      frame['month'] = month
      pieces.append(frame)
  
  names = pd.concat(pieces)
  print(names)
  </code></pre>
  
  <p>I used the append(), so the list was added in the below. </p>