title: spark scala - Merge mutiple rows into one
body: <p>I have a dataframe</p>
  
  <pre><code>|--id:string (nullable = true)
  |--ddd:struct (nullable = true)
    |-- aaa: string (nullable = true)
    |-- bbb: long(nullable = true)
    |-- ccc: string (nullable = true)
    |-- eee: long(nullable = true)
  </code></pre>
  
  <p>I am having output like this</p>
  
  <pre><code> id     |  ddd
  --------------------------
     1    | [hi,1,this,2]
     2    | [hello,6,good,3]
     1    | [hru,2,where,7]
     3    | [in,4,you,1]
     2    | [how,4,to,3]
  </code></pre>
  
  <p>I want the expected o/p as:</p>
  
  <pre><code>   id   |  ddd
    --------------------
     1    | [hi,1,this,2],[hru,2,where,7]
     2    | [hello,6,good,3],[how,4,to,3]
     3    | [in,4,you,1]
  </code></pre>
  
  <p>Please help</p>