title: How to filter out values from pyspark.rdd.PipelinedRDD?
body: <p>I have a <code>pyspark.rdd.PipelinedRDD</code> called <code>myRDD</code>. This is its sample content:</p>
  
  <pre><code>[((111, u'BB', u'A'), (444, u'BB', u'A')),
   ((222, u'BB', u'A'), (888, u'BB', u'A')),
   ((333, u'BB', u'B'), (999, u'BB', u'A')),...]
  </code></pre>
  
  <p>I need to delete all entries where the third column values do not coincide. The expected result is this one:</p>
  
  <pre><code>[((111, u'BB', u'A'), (444, u'BB', u'A')),
   ((222, u'BB', u'A'), (888, u'BB', u'A')),...]
  </code></pre>
  
  <p>How can I do it?</p>