title: Pandas partial transpose
body: <p>I want to reformat a dataframe by transeposing some columns with fixing other columns.</p>
  
  <p>original data :</p>
  
  <pre><code>ID  subID  values_A  
  --  -----  --------  
  A    aaa     10      
  B    baa     20      
  A    abb     30      
  A    acc     40      
  C    caa     50      
  B    bbb     60      
  </code></pre>
  
  <p>Pivot once : </p>
  
  <pre><code> pivot_table( df, index = ["ID", "subID"] )
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code>ID  subID  values_A 
  --  -----  -------- 
  A    aaa     10     
       abb     30     
       acc     40     
  
  B    baa     20     
       bbb     60     
  
  C    caa     50     
  </code></pre>
  
  <p>What I want to do ( Fix ['ID'] columns and partial transpose ) : </p>
  
  <pre><code>ID  subID_1  value_1   subID_2  value_2  subID_3  value_3
  --  -------  -------  --------  -------  -------  -------
  A    aaa       10       abb       30       acc       40
  B    baa       20       bbb       60       NaN       NaN 
  C    caa       50       NaN       NaN      NaN       NaN 
  </code></pre>
  
  <p>what I know max subIDs count value which are under each IDs.</p>
  
  <p>I don't need any calculating value when pivot and transepose dataframe.</p>
  
  <p>Please help</p>