title: Spliting a Dataframe with unique and duplicates
body: <p>Input Dataframe : </p>
  
  <pre><code>df=
  +---+---+---+---+---+
  |  1|  2|  3|  4|  5|
  +---+---+---+---+---+
  |  a|  b|  c|  d|  E|
  |  a|  b|  c|  d|  F|
  |  a|  b|  d|  d|  H|
  |  a|  c|  c|  d|  E|
  |  a|  a|  c|  d|  E|
  |  a|  b|  c|  d|  L|
  |  a|  c|  c|  d|  E|
  +---+---+---+---+---+`
  </code></pre>
  
  <p>code</p>
  
  <pre><code>String[] col={"1", "2","3"};
  Dataframe a=df.dropDuplicates(col);
  Dataframe b=df.except(a);
  </code></pre>
  
  <pre><code>a.show();
  +---+---+---+---+---+
  |  1|  2|  3|  4|  5|
  +---+---+---+---+---+
  |  a|  a|  c|  d|  E|
  |  a|  b|  c|  d|  E|
  |  a|  b|  d|  d|  H|
  |  a|  c|  c|  d|  E|
  +---+---+---+---+---+`
  
  b.show();
  +---+---+---+---+---+
  |  1|  2|  3|  4|  5|
  +---+---+---+---+---+
  |  a|  b|  c|  d|  L|
  |  a|  b|  c|  d|  F|
  +---+---+---+---+---+`
  </code></pre>
  
  <p>But I need a output for b is </p>
  
  <pre><code>b.show();
  +---+---+---+---+---+
  |  1|  2|  3|  4|  5|
  +---+---+---+---+---+
  |  a|  b|  c|  d|  L|
  |  a|  b|  c|  d|  F|
  |  a|  c|  c|  d|  E|
  +---+---+---+---+---+
  </code></pre>