发现类型不匹配:预期单位:RDD [XYZ ...] [英] type mismatch found : Unit expected : RDD[XYZ...]

问题描述

在以下情况下，我遇到类型不匹配错误

I'm getting type mismatch error for below scenario

//scores sample file  
0000006,Danny,6.2  
0000002,Danny,7.0  

代码.

 case class Person(id: String, dob: String, country: String, score: Double) 

 def getResultRecords(persons: RDD[List[String]]): RDD[Person] = {

   val personUS = persons.map(rec => Person(rec.head, rec(1),"US"), java.lang.Double.parseDouble(cpg.getOrElse(rec.head,"0").toString())
   val personMX = persons.map(rec => Person(rec.head, rec(1),"MX"),java.lang.Double.parseDouble(cpg.getOrElse(rec.head,"0").toString()))
   val personAll = personUS.union(personMX)
   //return personAll
}//Getting an error saying " type mismach found : Unit expected : RDD[Person]"

我在这里做错了什么?我该如何解决?

What am I doing wrong here? How can I fix it?

请帮助我.

推荐答案

您的方法签名为 def getResultRecords(persons:RDD [List [String]]):RDD [Person] ;这意味着该方法应返回 RDD [Person] 的实例.

YOur method signature is def getResultRecords(persons: RDD[List[String]]): RDD[Person]; that means the method should return an instance of RDD[Person].

但是，同一方法的最后一行说- val personAll = personUS.union(personMX)-不返回任何内容.

However, the last line of that same method says - val personAll = personUS.union(personMX) - which returns nothing.

取消注释 return personAll 行-这将清除您的异常.

Uncomment return personAll line - and this will erase your exception.

此外，我发现您的语法有问题.

Also, I found some issue with your syntax.

这是您的代码段.

case class Person(id: String, dob: String, country: String, score: Double) 

def getResultRecords(persons: RDD[List[String]]): RDD[Person] = {

  val personUS = persons.map(rec => Person(rec.head, rec(1),"US", java.lang.Double.parseDouble(cpg.getOrElse(rec.head,"0").toString()))
  val personMX = persons.map(rec => Person(rec.head, rec(1),"MX",java.lang.Double.parseDouble(cpg.getOrElse(rec.head,"0").toString()))
  val personAll =  personUS.union(personMX)
  return personAll
}

此处提供了额外的括号)- Person(rec.head，rec(1)，"US" .并且 return 语句已被注释掉.

An extra parenthesis ) is given here - Person(rec.head, rec(1),"US". And return statement was commented out.

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