title: how to deal with error SPARK-5063 in spark
body: <p>I get the error message SPARK-5063 in the line of println</p>
  
  <pre><code>val d.foreach{x=&gt; for(i&lt;-0 until x.length)
        println(m.lookup(x(i)))}    
  </code></pre>
  
  <p>d is  <code>RDD[Array[String]]</code>  m is <code>RDD[(String, String)]</code> . Is there any way to print as the way I want? or how can i convert d from <code>RDD[Array[String]]</code>  to <code>Array[String]</code> ?</p>