Arrays 第二个参数替换第一个scala

我试图在scala（^）中定义一个函数，它接受2个值并按如下方式打印它们

 2
x

这是我到目前为止所拥有的

class $ (val text2D: Array[Array[Char]])
{
  def ^(that: $) =
  {
    " " ++ s"${this.text2D(0)(0)}" ++
    "\n" ++ s"${that.text2D(0)(0)}"
  }

  def +(that: $) = this.text2D + "+" + that.text2D

  override def toString = s"${this.text2D(0)(0)}"
}

object $ {
  val array = Array.ofDim[Char](1,1)
  def apply(x: String): $ = {
    array (0)(0) = x.charAt(0)
    new $ (array)
  }
}

val x = $("x")
println(x)

val x2 = $("x") ^ $("2")
println(x2)

当我运行它时，我没有得到我期望的输出，而是得到了

 2
2

---

为什么它只接受第二个元素？任何帮助都将不胜感激。

对象

创建一个单例，因此您使用的（可变）数组将在调用

应用

之间共享。您需要在

apply

调用中分配该数组

def apply(x: String): $ = {
  val array = Array.ofDim[Char](1,1)
  array (0)(0) = x.charAt(0)
  new $ (array)
}

还有，有点不相关，但我相信你的论点是相反的。要获得所需的输出，您需要

" " ++ s"${that.text2D(0)(0)}" ++
"\n" ++ s"${this.text2D(0)(0)}"

---

我想你需要的是这样的东西：

class $(val text2D: Array[String]) {
  def ^(that: $): $ = {
    if (this.text2D.length == 0)
      that
    else if (that.text2D.length == 0)
      this
    else {
      val thisW = this.text2D(0).length
      val thatW = that.text2D(0).length

      // cross-pad arrays to have the same width
      val padThisRight = " " * thatW
      val padThatLeft = " " * thisW
      val thisPaddedW = this.text2D.map(_ + padThisRight)
      val thatPaddedW = that.text2D.map(padThatLeft + _)
      // first lines comes from that!
      new $(thatPaddedW ++ thisPaddedW)
    }
  }

  def +(that: $): $ = {
    if (this.text2D.length == 0)
      that
    else if (that.text2D.length == 0)
      this
    else {
      val thisH = this.text2D.length
      val thatH = that.text2D.length
      val thisW = this.text2D(0).length
      val thatW = that.text2D(0).length

      // pad arrays to have the same height
      val emptyThis = " " * thisW
      val emptyThat = " " * thatW
      val thisPaddedH = if (thisH >= thatH) this.text2D else Array.fill(thatH - thisH)(emptyThis) ++ this.text2D
      val thatPaddedH = if (thisH <= thatH) that.text2D else Array.fill(thisH - thatH)(emptyThat) ++ that.text2D

      new $(thisPaddedH.zip(thatPaddedH).map(p => p._1 + p._2))
    }
  }

  override def toString = text2D.mkString("\n")
}

object $ {
  def apply(x: String): $ = {
    new $(Array[String](x))
  }
}

产生以下输出

x2:
 2
x 
----------------------------
z:
 2    2
x  + y 
----------------------------
zz:
       3
 2    2 
x  + y  
----------------------------

这里的主要思想是，对

$

的操作会生成另一个

$

实例，而不是

字符串

（我使用

字符串

，而不是

数组[Char]

，因为它看起来容易得多，也没有明显的缺点）。这样，您就不必重新解析

String

并将其按新行拆分，也不必考虑如何处理字符串未对齐的情况。所以现在操作符

^

和

+

只是一个练习，将两个2d数组对齐，使其具有相同的宽度或高度，然后将它们连接起来

x2:
 2
x 
----------------------------
z:
 2    2
x  + y 
----------------------------
zz:
       3
 2    2 
x  + y  
----------------------------