我是 scala 的新手,我正在尝试执行以下代码:
val SetID = udf{(c:String, d: String) =>
if( c.UpperCase.contains("EXKLUS") == true)
{d}
else {""}
}
val ParquetWithID = STG1
.withColumn("ID", SetID( col("line_item"), col("line_item_ID")))
两个列(line_item
和line_item_id
)在Strings
架构中定义为STG1
。
当我尝试运行代码时出现以下错误:
`org.apache.spark.SparkException: Failed to execute user defined function($anonfun$1$$anonfun$2: (string, string) => string)
at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIterator.processNext(Unknown Source)
at org.apache.spark.sql.execution.BufferedRowIterator.hasNext(BufferedRowIterator.java:43)
at org.apache.spark.sql.execution.WholeStageCodegenExec$$anonfun$8$$anon$1.hasNext(WholeStageCodegenExec.scala:370)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$4.apply(SparkPlan.scala:246)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$4.apply(SparkPlan.scala:240)
at org.apache.spark.rdd.RDD$$anonfun$mapPartitionsInternal$1$$anonfun$apply$24.apply(RDD.scala:803)
at org.apache.spark.rdd.RDD$$anonfun$mapPartitionsInternal$1$$anonfun$apply$24.apply(RDD.scala:803)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:319)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:283)
at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:70)
at org.apache.spark.scheduler.Task.run(Task.scala:86)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:274)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
和
Caused by: java.lang.NullPointerException
at MyTests$$anonfun$1$$anonfun$2.apply(MyTests.scala:356)
at MyTests$$anonfun$1$$anonfun$2.apply(MyTests.scala:355)
... 16 more
我也试过c.UpperCase().contains("EXKLUS")
,但我得到了同样的错误。
但是,如果我只是运行一个" if equals
"声明一切正常。所以我想问题是在UpperCase().contains(" ")
中使用udf
函数,但我不明白问题的来源。任何帮助都会得到满足!
答案 0 :(得分:1)
如果schema
包含
|-- line_item: string (nullable = true)
|-- line_item_ID: string (nullable = true)
然后在if语句中检查null
应解决问题(注意字符串有toUpperCase
方法)
val SetID = udf{(c:String, d: String) =>
if(c != null && c.toUpperCase.contains("EXKLUS") == true)
{d}
else {""}
}
val ParquetWithID = STG1
.withColumn("ID", SetID( col("line_item"), col("line_item_ID")))
我希望答案很有帮助