python出现TypeError: sequence item 1: expected string or Unicode, int found

1、当运行python出现TypeError: sequence item 1: expected string or Unicode, int found，如下错误信息：

org.apache.spark.api.python.PythonException: Traceback (most recent call last):
  File "/usr/local/src/spark-1.6.3-bin-hadoop2.6/python/lib/pyspark.zip/pyspark/worker.py", line 111, in main
    process()
  File "/usr/local/src/spark-1.6.3-bin-hadoop2.6/python/lib/pyspark.zip/pyspark/worker.py", line 106, in process
    serializer.dump_stream(func(split_index, iterator), outfile)
  File "/usr/local/src/spark-1.6.3-bin-hadoop2.6/python/lib/pyspark.zip/pyspark/serializers.py", line 133, in dump_stream
    for obj in iterator:
  File "/usr/local/src/spark-1.6.3-bin-hadoop2.6/python/lib/pyspark.zip/pyspark/rdd.py", line 1494, in func
  File "/sunxj/spark/pyspark/wordcount_1.py", line 18, in 
    result = rdd.flatMap(f).map(lambda word:(word,1)).reduceByKey(lambda a,b:a+b).sortBy(lambda x:x[1],ascending=False).map(lambda x:'\t'.join([x[0],x[1]]))
TypeError: sequence item 1: expected string or Unicode, int found

	at org.apache.spark.api.python.PythonRunner$$anon$1.read(PythonRDD.scala:166)
	at org.apache.spark.api.python.PythonRunner$$anon$1.(PythonRDD.scala:207)
	at org.apache.spark.api.python.PythonRunner.compute(PythonRDD.scala:125)
	at org.apache.spark.api.python.PythonRDD.compute(PythonRDD.scala:70)
	at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306)
	at org.apache.spark.rdd.RDD.iterator(RDD.scala:270)
	at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
	at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306)
	at org.apache.spark.rdd.RDD.iterator(RDD.scala:270)
	at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
	at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306)
	at org.apache.spark.rdd.RDD.iterator(RDD.scala:270)
	at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:66)
	at org.apache.spark.scheduler.Task.run(Task.scala:89)
	at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:227)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)

如下图所示：

2、出现此错误表示在输出时，不能以int方式进行join，如下代码x[1]是一个数字：

3、只需要将x[1]通过str转换成字符串即可，如下图所示：