Question

我有以下列表作为输入：

val lisinputt=("banana  10",
          "apple   20",
          "apple   30",
          "banana   10",  
          "berry    10")

我想计算每个元素的出现次数，而不是与每个元素相关的和值，因此想要的输出将是：

val listoutput=("banana  2 20",
          "apple 2  50",  
          "berry  1  10")

请知道如何实现这一目标

Answer 1

您可以执行以下操作

val lisinputt=("banana  10",
  "apple   20",
  "apple   30",
  "banana   10",
  "berry    10")

lisinputt.productIterator.toList
  .map(x => {val splitted = x.toString.split("\\s+"); (splitted(0), 1, splitted(1))})
  .groupBy(_._1)
  .mapValues(x => (x.map(_._2.toInt).sum, x.map(_._3.toInt).sum))
  .map(x => Array(x._1, x._2._1, x._2._2).mkString(" "))
  .foreach(println)

应该给你

banana 2 20
apple 2 50
berry 1 10

Answer 2

你可以期待像这样的输出

val listInput=("banana  10",
  "apple   20",
  "apple   30",
  "banana   10",
  "berry    10")
val result = listInput.productIterator.toList.map(_.toString.split("\\s+")).groupBy(e=> e.apply(0)).collect{
  case e=> (e._1, e._2.size, e._2.map(_.apply(1).toInt).sum)
}
//result: scala.collection.immutable.Iterable[(String, Int, Int)] = List((banana,2,20), (apple,2,50), (berry,1,10))

scala计算元素的出现次数

2 个答案: