无法解析重载方法'groupByKey'

Question

我正在尝试编译此代码：

// Imports
import org.apache.spark.sql.{Row, SQLContext, SparkSession}
import org.apache.spark.sql.types._
import org.apache.spark.{SparkConf, SparkContext}

...

// Initialization
val conf = new SparkConf().setAppName("spark-test").setMaster("local")
val sc = new SparkContext(conf)
val sparkSession = SparkSession.builder.config(sc.getConf).getOrCreate()
import sparkSession.implicits._

...

val sqlContext = sparkSession
val dfPlayersT = sqlContext.createDataFrame(nPlayer,schemaN)

dfPlayersT.createOrReplaceTempView("tPlayers")
val dfPlayers = sqlContext.sql("select age-min_age as exp,tPlayers.* from 
  tPlayers join (select name,min(age)as min_age from tPlayers group by name) 
     as t1 on tPlayers.name=t1.name order by tPlayers.name, exp ")


val pStats = dfPlayers.sort(dfPlayers("name"),dfPlayers("exp").asc)
  .map(x=>(x.getString(1),(x.getDouble(50),x.getDouble(40),x.getInt(2),
    x.getInt(3),Array(x.getDouble(31),x.getDouble(32),x.getDouble(33),
    x.getDouble(34),x.getDouble(35),x.getDouble(36),x.getDouble(37),
    x.getDouble(38),x.getDouble(39)),x.getInt(0))))
    .groupByKey()  // Error

但是得到一个错误：

Error:(217, 57) overloaded method value groupByKey with alternatives:
  [K](func: org.apache.spark.api.java.function.MapFunction[(String, (Double, Double, Int, Int, Array[Double], Int)),K], encoder: org.apache.spark.sql.Encoder[K])org.apache.spark.sql.KeyValueGroupedDataset[K,(String, (Double, Double, Int, Int, Array[Double], Int))] <and>
  [K](func: ((String, (Double, Double, Int, Int, Array[Double], Int))) => K)(implicit evidence$4: org.apache.spark.sql.Encoder[K])org.apache.spark.sql.KeyValueGroupedDataset[K,(String, (Double, Double, Int, Int, Array[Double], Int))]
 cannot be applied to ()
        x.getDouble(38),x.getDouble(39)),x.getInt(0)))).groupByKey()

这是我的build.sbt文件：

name := "ScalaHello"

version := "0.1"

scalaVersion := "2.12.8"

libraryDependencies += "org.apache.spark" %% "spark-core" % "2.4.2"
libraryDependencies += "org.apache.spark" %% "spark-catalyst" % "2.4.2"
libraryDependencies += "org.apache.spark" %% "spark-sql" % "2.4.2"

我认为问题是关于sparkSession的初始化，但是不能得到什么错误。

Answer 1

应该是吗？

.groupByKey(_._1)

要么

.groupByKey(_._2._1) 

要么

.groupByKey(_._2._2)

...

要么

.groupByKey(_._2._6)  

?