title: Filter rdd lines by values in fields Scala
body: <p>I have a csv that has the following structure:</p>
  
  <blockquote>
    <p>header,header,header,header,header<br>
    val1,  val2,  val3,  val4,  val5<br>
    val1,  val2,  null,  val4,  val5<br>
    val1,  val2,  val3,  null,  val5</p>
  </blockquote>
  
  <p>What I need to do is filter out the header and the lines of data that contain null values at particular locations(it is OK to have a null at val3 but not val4).  I made an rdd and split the lines on the commas, my hope was to access each line like an index location of an array.    But I can not find out how to do the comparison.  I can extract fields with:</p>
  
  <blockquote>
    <p>rdd.map(values=>(values(2))   </p>
  </blockquote>
  
  <p>How do you do the comparison?  Particularly the "does not contain".  I would think there is a comparison method available or does this problem require a tuple  and !contain?                          </p>