Question

当我在数据框上运行show方法时出现以下错误。

Py4JJavaError: An error occurred while calling o14904.showString.
: org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 23450.0 failed 1 times, most recent failure: Lost task 0.0 in stage 23450.0 (TID 120652, localhost): org.apache.spark.api.python.PythonException: Traceback (most recent call last):
  File "/Users/i854319/spark2/python/lib/pyspark.zip/pyspark/worker.py", line 172, in main
    process()
  File "/Users/i854319/spark2/python/lib/pyspark.zip/pyspark/worker.py", line 167, in process
    serializer.dump_stream(func(split_index, iterator), outfile)
  File "/Users/i854319/spark2/python/lib/pyspark.zip/pyspark/serializers.py", line 263, in dump_stream
    vs = list(itertools.islice(iterator, batch))
  File "<ipython-input-8-b76896bc4e43>", line 320, in <lambda>
UnicodeEncodeError: 'ascii' codec can't encode characters in position 3-5: ordinal not in range(128)

    at org.apache.spark.api.python.PythonRunner$$anon$1.read(PythonRDD.scala:193)
    at org.apache.spark.api.python.PythonRunner$$anon$1.next(PythonRDD.scala:156)

当我只获取12行时，它不会抛出错误。

jpsa_rf.features_df.show(12)
+------------+--------------------+
|Feature_name|    Importance_value|
+------------+--------------------+
| competitive|0.019380017988201638|
|         new|0.012416277407924172|
|self-reliant|0.009044388916918005|
|     related|0.008968947484358822|
|      retail|0.008729510712416655|
|      sales,|0.007680271475590303|
|        work|0.007548541044789985|
| performance|0.007209008630295571|
|    superior|0.007065626808393139|
|     license|0.006436001036918034|
|    industry|0.006416712169788629|
|      record|0.006227581067732823|
+------------+--------------------+
only showing top 12 rows

但是当我这样做时。显示（15）我得到了错误。

我创建了这个数据框，如下所示：它基本上是一个特征数据框，其重要值来自随机森林模型

vocab=np.array(self.cvModel.bestModel.stages[3].vocabulary)
        if est_name=="rf":
            feature_importance=self.cvModel.bestModel.stages[5].featureImportances.toArray()
            argsort_feature_indices=feature_importance.argsort()[::-1]
        elif est_name=="blr":
            feature_importance=self.cvModel.bestModel.stages[5].coefficients.toArray()
            argsort_feature_indices=abs(feature_importance).argsort()[::-1]
        # Sort the features importance array in descending order and get the indices

        feature_names=vocab[argsort_feature_indices]

        self.features_df=sc.parallelize(zip(feature_names,feature_importance[argsort_feature_indices])).\
        map(lambda x: (str(x[0]),float(x[1]))).toDF(["Feature_name","Importance_value"])

Answer 1

我假设您正在使用Python 2.手头的问题很可能是您str(x[0])中的df.map部分。似乎x[0]引用了一个unicode字符串，str应该将它转换为bytestring。然而，它是通过隐式假设ASCII编码来实现的，这种编码仅适用于纯英文文本。

这不是应该如何完成的事情。

简短的回答是：将str(x[0])更改为x[0].encode('utf-8')。

可以找到长答案，例如here或here。

将RDD转换为Spark DataFrame时出现Unicode错误

1 个答案: