title: Python dataframe reformat to multi-index
body: <p>How can I convert the below origin dataframe into the output dataframe please?</p>
  
  <p><strong><em>origin:</em></strong></p>
  
  <pre><code>**Date, Name, P1, P2**    
  date1, name1, 2.0, 3.0
  date2, name1, 3.1, 2.3
  date1, name2, 3.4, 2.4
  date2, name2, 2.0, 3.0
  </code></pre>
  
  <p><strong><em>output:</em></strong></p>
  
  <pre><code>**name1, name2**
  **DATE**   **P1, P2; P1; P2**
  date1, 2.0, 3.0; 3.4, 2.4
  date2, 3.1, 2.3; 2.0, 3.0
  </code></pre>
  
  <p>I thought of a trouble way to do it, which is to filter the name and concat the result dataframe blocks. But it seems quite stupid the way. any chance you guys can help please? </p>