title: Pandas dataframe transpose with original row and column values
body: <p>Does anyone know how to transpose pandas dataframe with original row and column values? I am looping through each row and column using .iterrows() but I am sure there is a better way to do this. Maybe using pivot? Thanks!</p>
  
  <p>DF looks like</p>
  
  <pre><code>    a   b   c
  0   11  12  13
  1   21  22  23
  2   31  32  33
  </code></pre>
  
  <p>I want the new DF to be</p>
  
  <pre><code>    row col Val
  0   0   a   11
  1   0   b   12
  2   0   c   13
  3   1   a   21
  4   1   b   22
  5   1   c   23
  6   2   a   31
  7   2   b   32
  8   2   c   33
  </code></pre>