title: Reshaping Spark RDD - KV pairs
body: <p>Is there a way to reshape a spark RDD in this manner. Essentially the opposite of this:
  <a href="https://stackoverflow.com/questions/42085212/reshaping-spark-rdd">Reshaping Spark RDD</a></p>
  
  <p>Suppose I have:</p>
  
  <pre><code>[['id1', 'v1', 'v2', 'v3', 'v4'], ['id2', 'v1', 'v2', 'v3']]
  </code></pre>
  
  <p>And want:</p>
  
  <pre><code>[['id1','v1'],
   ['id1','v2'],
   ['id1','v3'],
   ['id1','v4'],
   ['id2','v1'],
   ['id2','v2'],
   ['id2','v3']]
  </code></pre>
  
  <p>Noting that there are differing amounts of variables in each row.</p>