title: Python Pandas copy columns from one sheet to another sheet without changing any data?
body: <p>I have an excel file with two sheets. I would like to copy 3 columns from the first sheet to the second sheet.</p>
  
  <p>Note:     </p>
  
  <ul>
  <li>the copied 3 column’s label names have some duplicates with the second sheet. But I should <strong>keep the original data of the second sheet without changing them</strong>.    </li>
  <li><p>I have tried many methods. My best attempt so far is :     </p>
  
  <pre><code>df_new_sheet2 = pd.concat([df_old_sheet2, df_three_of_sheet1], axis=1, join_axes=[df_old_sheet2.index])     
  </code></pre></li>
  </ul>
  
  <p>But this is not the desired output.</p>
  
  <p>If pandas can not do this, could you please suggest some other python package which could work ?</p>
  
  <p>In case I'm not describing the problem clearly enough, I upload a pic which may help more or less. Thx for your answers~      </p>
  
  <p><img src="https://i.stack.imgur.com/8WJIY.jpg" alt="jpg">    </p>
  
  <p>UPDATE[2017.07.24]:    </p>
  
  <p>I Finally find my fault!    </p>
  
  <p><strong>insert one column with index number and then , follow the resolution of b2002, things gonna to be well. :)</strong></p>