title: Add a new column to a Dataframe. New column i want it to be a UUID generator
body: <p>I want to add a new column to a Dataframe, a UUID generator.</p>
  
  <p>UUID value will look something like <code>21534cf7-cff9-482a-a3a8-9e7244240da7</code></p>
  
  <p>My Research:</p>
  
  <p>I've tried with <code>withColumn</code> method in spark.</p>
  
  <pre><code>val DF2 = DF1.withColumn("newcolname", DF1("existingcolname" + 1)
  </code></pre>
  
  <p>So DF2 will have additional column with <code>newcolname</code> with 1 added to it in all rows.</p>
  
  <p>By my requirement is that I want to have a new column which can generate the UUID.</p>