Question

我需要计算Scala中三个年龄段的平均值。我尝试过下面显示的方法，但它没有用。请帮忙。

sealed abstract class Component
case class Life (age:Int) extends Component

object Life extends Component{
  def main(args: Array[String]){
    val lives = List{Life(10), Life(20), Life(30)}
    def livesMean (l:List[Life]):Double = {
        println(livesMean)
    }
  }
}

Answer 1

首先，您已经错误地声明了生命对象列表。并找到平均值，取出年龄之和并将其除以列表大小。

sealed abstract class Component
case class Life (age:Int) extends Component

object Main extends Component{
    def main(args: Array[String]){
    val lives = List(Life(10), Life(20), Life(30))
    def livesMean (l:List[Life]):Double = lives.map(_.age).sum/lives.size
    println("average of lives "+ livesMean(lives))
  }
}

正在运行。你可以看到它here

Answer 2

您用于创建lives的语法无效。这应该有效：

abstract class Component

case class Life(age: Int) extends Component

object Life extends Component {
    def main(args: Array[String]) {
        val lives = List(new Life(10), new Life(20), new Life(30))
        val livesMean: Double = lives.map(_.age).sum / lives.size
        println(livesMean) // 20.0
    }
}

斯卡拉小提琴：https://scalafiddle.io/sf/Lyu9VRf/0

计算Scala平均值

2 个答案: