Scala Real Interval,Int Interval

发布时间：2020-12-16 18:37:55 所属栏目：安全来源：网络整理

导读：如何定义这两个简单Interval类的锅炉板消除超类？ class IntInterval(val from: Int,val to: Int) { def mid: Double = (from+to)/2.0 def union(other: IntInterval) = IntInterval(from min other.from,to max other.to)}class DoubleInterval(val from: D

如何定义这两个简单Interval类的锅炉板消除超类？

class IntInterval(val from: Int,val to: Int) { 
    def mid: Double = (from+to)/2.0 
    def union(other: IntInterval) = IntInterval(from min other.from,to max other.to)
}

class DoubleInterval(val from: Double,val to: Double) { 
    def mid: Double = (from+to)/2.0 
    def union(other: DoubleInterval) = DoubleInterval(from min other.from,to max other.to)
}

我试过了

class Interval[T <: Number[T]] (val from: T,val to: T) { 
    def mid: Double = (from.doubleValue+to.doubleValue)/2.0 
    def union(other: IntInterval) = Interval(from min other.from,to max other.to)
}

但是min和max没有在union方法中编译(因为Number [T]没有min / max).

你能提供一个优雅的超类,它以简洁,一次又一次的模板避免方式处理mid和union方法吗？

解决方法

我想你正在寻找scala.math.Numeric类型类：

class Interval[T] (val from: T,val to: T)(implicit num: Numeric[T]) { 
  import num.{mkNumericOps,mkOrderingOps}

  def mid: Double  = (from.toDouble + to.toDouble)/2.0 
  def union(other: Interval[T]) = new Interval(from min other.from,to max other.to)
}

（编辑：李大同）

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