如何将参数传递给Scala中的方法

Question

我试图将第四个（targetFileCount）参数传递给下面的方法

val config = ConfigFactory.load("market_opt_partition.properties")
val targetFileCount = (config.getInt(Code))
writeArray1.par.foreach {
  case (df, path, tog, targetFileCount) => Utility.write(df, path, tog, targetFileCount)
}
object Utility {
    def write(sourceDf: DataFrame, path: String, toggle: String, targetFileCount:Int): Unit

但是我面临以下错误，

Error:(368, 12) constructor cannot be instantiated to expected type;
found   : (T1, T2, T3, T4)
required: (org.apache.spark.sql.DataFrame, String, String)
      case (df, path, tog, targetFileCount) => Utility.write(df, path, tog, targetFileCount)
Error:(368, 67) not found: value df
      case (df, path, tog, targetFileCount) => Utility.write(df, path, tog, targetFileCount)

请让我知道如何纠正相同。

Answer 1

writeArray1包含 org.apache.spark.sql.DataFrame, String, String的元组3因此，在4个参数上匹配的模式匹配无法正常工作。

另一个示例：

val l = List(5)
l.map { case (a, b) => a.toString }

也产生相同的错误：

 error: constructor cannot be instantiated to expected type;
 found   : (T1, T2)
 required: Int

Answer 2

如上所述writearray1.par包含3 org.apache.spark.sql.dataframe的元组，string，string，string so so so so params上的模式无法正常工作。

请使用以下。

val config = ConfigFactory.load("market_opt_partition.properties")
val targetFileCount = (config.getInt(Code))
writeArray1.par.foreach {
  case (df, path, tog) => Utility.write(df, path, tog, targetFileCount)
}
object Utility {
    def write(sourceDf: DataFrame, path: String, toggle: String, targetFileCount:Int): Unit