在Scala中添加數組元素

Question

因此，我正在學習Scala並嘗試創建一個基於數組的向量類，並創建一個添加和減法運算符以添加2個向量。這是我迄今爲止所做的。任何人都可以幫助弄清楚如何製作它，以便當我添加到不同長度的矢量時，它會向長度較短的數組添加「0」，以使其長度等於長度較長的數組。像添加(1, 2)到(1, 2, 3)應該返回(2, 4, 3)

class Wektor(private val s: Array[Double]){ 
     class LengthNotEqualException(msg:String) extends Exception(msg) 
     def get(index: Int):Double= s(index) 
     def +(that: Wektor):Wektor= 
      if(this.s.length != that.s.length) 
        throw new LengthNotEqualException("Wektory roznej dlugosci") 
      else 
      { 
      val temp= new Array[Double](this.s.length) 
      var i:Int= 0 
       for(i <- 0 until this.s.length) 
      { 
       temp(i)= this.s(i) + that.get(i) 
      } 
      new Wektor(temp) // zwraca nowy Wektor będący sumą danych wektorów 
      } 
     def -(that: Wektor):Wektor= 
      if(this.s.length != that.s.length) 
        throw new LengthNotEqualException("Wektory roznej dlugosci") 
      else 
      { 
      val temp= new Array[Double](this.s.length) 
      var i= 0 
       for(i <- 0 until this.s.length) 
      { 
       temp(i)= this.s(i) - that.get(i) 
      } 
      new Wektor(temp) // zwraca nowy Wektor będący różnicą danych wektorów 
      } 
     def *+(that:Wektor):Double= 
      if(this.s.length != that.s.length) 
        throw new LengthNotEqualException("Wektory roznej dlugosci") 
      else 
       { 
        var result:Double= 0 
        var i:Int = 0 
        for(i <- 0 until this.s.length) 
        { 
       result= result + this.s(i) * that.get(i) 
        } 
        result  // zwracany iloczyn skalarny 
       } 
     override def toString():String={ 
      var result:String="Wektor: [" 
      var i:Int= 0 
      for(i <- 0 until this.s.length) 
      { 
        result= result + this.s(i) + " " 
      } 
      result = result + "]" 
      result  // zwracana wartosc 
     } 
} 

val test= new Wektor(Array[Double](1, 2, 3,5)) 
val test2= new Wektor(Array[Double](2, 2, 2)) 
val suma= test + test2 
val roznica= test - test2 
val iloczyn= test *+ test2 
println(suma) 
println(roznica) 
println(iloczyn) 

Answer 1

使用zipAll這樣的：

case class Wektor(inner: IndexedSeq[Double]) { 
    def +(that: Wektor) = 
    Wektor(this.inner.zipAll(that.inner, 0.0, 0.0).map{case (a, b) => a+b}) 
    def -(that: Wektor) = 
    Wektor(this.inner.zipAll(that.inner, 0.0, 0.0).map{case (a, b) => a-b}) 
    def *+(that: Wektor) = 
    this.inner.zipAll(that.inner, 1.0, 1.0).map{case (a, b) => a*b}.sum 

    override def toString() = inner.mkString("Wektor: [", " ", "]") 
} 

val a = Wektor((1 to 5).map{_.toDouble}) 
// Wektor: [1.0 2.0 3.0 4.0 5.0] 
val b = Wektor((1 to 3).map{_.toDouble}) 
// Wektor: [1.0 2.0 3.0] 

a + b 
// Wektor: [2.0 4.0 6.0 4.0 5.0] 

a - b 
// Wektor: [0.0 0.0 0.0 4.0 5.0] 

a *+ b 
// 23.0