title: Apache Spark Not able to view output
body: <p>I have just started learning Apache Spark. I am trying to print the output of links but it doesn't display it for some reason. I have also tried links.collect() , display(links) but none of them work. Any help would be appreciated.</p>
  
  <p><a href="https://i.stack.imgur.com/mtBl4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mtBl4.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/dPdrR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dPdrR.png" alt="enter image description here"></a></p>
  
  <p>Complete Stack trace for second image:</p>
  
  <pre><code> Py4JJavaError                             Traceback (most recent call last)
    &lt;ipython-input-34-01e857cfa45e&gt; in &lt;module&gt;()
    ----&gt; 1 for link in links.collect():
          2         print("%s" %(link))
  
    /databricks/spark/python/pyspark/rdd.py in collect(self)
        769         """
        770         with SCCallSiteSync(self.context) as css:
    --&gt; 771             port = self.ctx._jvm.PythonRDD.collectAndServe(self._jrdd.rdd())
        772         return list(_load_from_socket(port, self._jrdd_deserializer))
        773 
  
    /databricks/spark/python/lib/py4j-0.9-src.zip/py4j/java_gateway.py in __call__(self, *args)
        811         answer = self.gateway_client.send_command(command)
        812         return_value = get_return_value(
    --&gt; 813             answer, self.gateway_client, self.target_id, self.name)
        814 
        815         for temp_arg in temp_args:
  
    /databricks/spark/python/pyspark/sql/utils.py in deco(*a, **kw)
         43     def deco(*a, **kw):
         44         try:
    ---&gt; 45             return f(*a, **kw)
         46         except py4j.protocol.Py4JJavaError as e:
         47             s = e.java_exception.toString()
  
    /databricks/spark/python/lib/py4j-0.9-src.zip/py4j/protocol.py in get_return_value(answer, gateway_client, target_id, name)
        306                 raise Py4JJavaError(
        307                     "An error occurred while calling {0}{1}{2}.\n".
    --&gt; 308                     format(target_id, ".", name), value)
        309             else:
        310                 raise Py4JError(
  
    Py4JJavaError: An error occurred while calling z:org.apache.spark.api.python.PythonRDD.collectAndServe.
    : org.apache.spark.SparkException: Job aborted due to stage failure: Task 4 in stage 24.0 failed 1 times, most recent failure: Lost task 4.0 in stage 24.0 (TID 76, localhost): org.apache.spark.api.python.PythonException: Traceback (most recent call last):
      File "/databricks/spark/python/pyspark/worker.py", line 111, in main
        process()
      File "/databricks/spark/python/pyspark/worker.py", line 106, in process
        serializer.dump_stream(func(split_index, iterator), outfile)
      File "/databricks/spark/python/pyspark/rdd.py", line 2346, in pipeline_func
        return func(split, prev_func(split, iterator))
      File "/databricks/spark/python/pyspark/rdd.py", line 2346, in pipeline_func
        return func(split, prev_func(split, iterator))
      File "/databricks/spark/python/pyspark/rdd.py", line 317, in func
        return f(iterator)
      File "/databricks/spark/python/pyspark/rdd.py", line 1776, in combineLocally
        merger.mergeValues(iterator)
      File "/databricks/spark/python/pyspark/shuffle.py", line 236, in mergeValues
        for k, v in iterator:
      File "&lt;ipython-input-31-4b09041aa30b&gt;", line 1, in &lt;lambda&gt;
      File "&lt;ipython-input-28-f43debc22073&gt;", line 3, in parseNeighbors
      File "/databricks/python/lib/python2.7/re.py", line 171, in split
        return _compile(pattern, flags).split(string, maxsplit)
    TypeError: expected string or buffer
  
      at org.apache.spark.api.python.PythonRunner$$anon$1.read(PythonRDD.scala:166)
      at org.apache.spark.api.python.PythonRunner$$anon$1.&lt;init&gt;(PythonRDD.scala:207)
      at org.apache.spark.api.python.PythonRunner.compute(PythonRDD.scala:125)
      at org.apache.spark.api.python.PythonRDD.compute(PythonRDD.scala:70)
      at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306)
      at org.apache.spark.rdd.RDD.iterator(RDD.scala:270)
      at org.apache.spark.api.python.PairwiseRDD.compute(PythonRDD.scala:342)
      at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306)
      at org.apache.spark.rdd.RDD.iterator(RDD.scala:270)
      at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:79)
      at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:46)
      at org.apache.spark.scheduler.Task.run(Task.scala:96)
      at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:222)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
      at java.lang.Thread.run(Thread.java:745)
  </code></pre>