AttributeError：“元组”对象在 pyspark 中没有属性“startswith”

Question

这是我使用的命令：

test=rdd.filter(lambda line:line.startsWith("I"))
test.take(2) 

当然，rdd 已经生成并且运行良好。但是测试不起作用并显示以下错误。

这个问题看起来很傻，但我对 Pyspark 不熟悉。我通过虚拟机在 pyspark 中遇到了这个错误。有谁知道这个错误是什么，请提供解决方案来解决它。感谢您提前提供任何帮助。

Py4JJavaError: An error occurred while calling z:org.apache.spark.api.python.PythonRDD.runJob.
: org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 24.0 failed 1 times, most recent failure: Lost task 0.0 in stage 24.0 (TID 13, localhost): org.apache.spark.api.python.PythonException: Traceback (most recent call last):
  File "/usr/lib/spark/python/pyspark/worker.py", line 101, in main
    process()
  File "/usr/lib/spark/python/pyspark/worker.py", line 96, in process
    serializer.dump_stream(func(split_index, iterator), outfile)
  File "/usr/lib/spark/python/pyspark/serializers.py", line 236, in dump_stream
    vs = list(itertools.islice(iterator, batch))
  File "/usr/lib/spark/python/pyspark/rdd.py", line 1221, in takeUpToNumLeft
    yield next(iterator)
  File "<ipython-input-44-6f0330afa2d7>", line 1, in <lambda>
AttributeError: 'tuple' object has no attribute 'startswith'

    at org.apache.spark.api.python.PythonRDD$$anon$1.read(PythonRDD.scala:135)
    at org.apache.spark.api.python.PythonRDD$$anon$1.<init>(PythonRDD.scala:176)
    at org.apache.spark.api.python.PythonRDD.compute(PythonRDD.scala:94)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:277)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:244)
    at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:61)
    at org.apache.spark.scheduler.Task.run(Task.scala:64)
    at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:203)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)

Driver stacktrace:
    at org.apache.spark.scheduler.DAGScheduler.org$apache$spark$scheduler$DAGScheduler$$failJobAndIndependentStages(DAGScheduler.scala:1203)
    at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1192)
    at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1191)
    at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
    at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
    at org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:1191)
    at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:693)
    at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:693)
    at scala.Option.foreach(Option.scala:236)
    at org.apache.spark.scheduler.DAGScheduler.handleTaskSetFailed(DAGScheduler.scala:693)
    at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:1393)
    at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:1354)
    at org.apache.spark.util.EventLoop$$anon$1.run(EventLoop.scala:48)

我的示例输入

[u'BibNumber,ItemBarcode,ItemType,Collection,CallNumber,CheckoutDateTime,,,,,,,',
 u'1842225,10035249209,acbk,namys,MYSTERY ELKINS1999,05/23/2005 03:20:00 PM,,,,,,,',
 u'1928264,10037335444,jcbk,ncpic,E TABACK,12/14/2005 05:56:00 PM,,,,,,,',
 u'1982511,10039952527,jcvhs,ncvidnf,VHS J796.2 KNOW_YO 2000,08/11/2005 01:52:00 PM,,,,,,,',
 u'2026467,10040985615,accd,nacd,CD 782.421642 Y71T,10/19/2005 07:47:00 PM,,,,,,,']

Answer 1

从错误来看，rdd 看起来不是 RDD[String] 而是 RDD[Tuple] 并且由于您尝试应用 startswith 这是一个 python 字符串函数，所以它失败了。

你可以试试这样的：

test = rdd.filter(lambda line: line[0][0].startsWith("I"))

上面将过滤你的RDD并返回元组的第一个元素以I开头的记录。