Question

我正在尝试将第四个（targetFileCount）参数传递给以下方法

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该问题。

Answer 1

writeArray1包含org.apache.spark.sql.DataFrame, String, String中的元组3 因此，无法在4个参数上进行模式匹配。

另一个例子：

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

也会产生相同的错误：

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

Answer 2

如上所述，writeArray1.par包含3个org.apache.spark.sql.DataFrame，String，String的元组，因此无法在4个参数上进行模式匹配。

请如下使用。

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

如何在scala中将参数传递给方法

2 个答案: