Scala中循环的减少？

使用Scala的第一天和第一次尝试-所以对我放松点！我正试图重写一些旧的Java代码，这只是一个函数，它接受两个数字并打印出从x到y的数字。例如，我有增量函数：

    def increment(start: Int, finish: Int) = {
      for (i <- start to finish) {
         println("Current value (increasing from "+start+" to "+finish+") is "+i)
      }
    }

def增量（开始：整数，结束：整数）={
为了
要排除第二条边界，请使用
直到
：

for (i <- (6 until 3 by -1)) {println ("i: " + i)}
i: 6
i: 5
i: 4

用于（i=停止））
def next:Int={
val res=当前值
如果（启动<停止）电流+=1，否则电流-=1
物件
} 
}
val it=新的FromToIterator（3,6）
val ti=新的FromToIterator（6,3）
对于（i
scala>def减量（开始：Int，结束：Int）={
|对于（i）减量（10，1）
当前值（从10降至1）为10
当前值（从10降至1）为9
当前值（从10降至1）为8
当前值（从10降至1）为7
当前值（从10降至1）为6
当前值（从10降至1）为5
当前值（从10降至1）为4
当前值（从10降至1）为3
当前值（从10减少到1）为2
当前值（从10减少到1）为1
以下是一个全局递增/递减解决方案，其灵感来自：

def goThrough（开始：Int，结束：Int）={
val d=if（开始时从高数值到低数值为-1（使用其他负或正步骤切换以更改步进）

def减量（开始：Int，结束：Int）={
对于（i
对象测试扩展应用程序{
def减量（开始：整数，结束：整数，结束：整数）={
对于（i
def printInDecreasingOrder）（开始：Int，结束：Int）{
如果（开始>结束）{
对于（i这种方式，您可以在Scala中使用递减for循环。

    object Example extends App {


      for(i <- 20 to 2 by -2){


        println("Value of i = "+ i)

      }
    }
------------------
O/P
------------------
Value of i = 20
Value of i = 18
Value of i = 16
Value of i = 14
Value of i = 12
Value of i = 10
Value of i = 8
Value of i = 6
Value of i = 4
Value of i = 2

对象示例扩展应用程序{
如果你这样做的话，我想给这个答案增加一点

for(j <- finish to start){......}

用于（j非常感谢。我现在不知道我怎么看不到这一点，因为我肯定没有直接思考！还有一件事-对不起。我如何在println中获得迭代器的值？
开始到结束时间-1
将返回一个可以迭代的
范围。是否仍有以函数形式编写此函数？
dec（start:Int，finish:Int）={start to finish by-1}；dec（10，1）。foreach（i=>println（“递减”+i））；
谢谢。我不知道
by-X
存在
class FromToIterator (start: Int, stop: Int) extends Iterator [Int] { 
  var current = start
  //                        3       6       3         6         6       3       6         3
  def hasNext : Boolean = ((start < stop && current <= stop) || (start > stop && current >= stop)) 
  def next: Int = { 
    val res = current
    if (start < stop) current += 1 else current -= 1
    res
  } 
}
val it = new FromToIterator (3, 6)
val ti = new FromToIterator (6, 3)

for (i <-it) println (i)
for (i <-ti) println (i)

scala>def decrement(start: Int, finish: Int) = {
    |  for (i <- start to finish by -1)
    |   println("Current value (decreasing from "+start+" to "+finish+") is "+i);
    | }
decrement: (start: Int,finish: Int)Unit

scala> decrement(10, 1)
Current value (decreasing from 10 to 1) is 10
Current value (decreasing from 10 to 1) is 9
Current value (decreasing from 10 to 1) is 8
Current value (decreasing from 10 to 1) is 7
Current value (decreasing from 10 to 1) is 6
Current value (decreasing from 10 to 1) is 5
Current value (decreasing from 10 to 1) is 4
Current value (decreasing from 10 to 1) is 3
Current value (decreasing from 10 to 1) is 2
Current value (decreasing from 10 to 1) is 1

def goThrough(start: Int, finish: Int) = {     
  val d = if(start<=finish) 1 else -1
  for (i <- start to finish by d) {
    println("Current value (increasing from "+start+" to "+finish+") is "+i)
  } 
}

def decrement(start: Int, finish: Int) = {
  for (i <- start to finish by -1) {
     println("Current value (decreasing from "+start+" to "+finish+") is "+i)
  }
}

object Test extends App{

  def decrement(start: Int, finish: Int,dec :Int) = {
    for (i <- Range(start,finish,dec)) {
      println("Current value (decreasing from "+start+" to "+finish+") is "+i)
    }
  }

  decrement(5,0,-1)
}

def printInDecreasingOrder(start : Int, end : Int){
  if(start > end ){
     for(i <- start to end by -1){
       println(s"Current value (decreasing from $start to $end) is $i")
     }
   }else{
     println("first num is smaller than second")
   }
}

    object Example extends App {


      for(i <- 20 to 2 by -2){


        println("Value of i = "+ i)

      }
    }
------------------
O/P
------------------
Value of i = 20
Value of i = 18
Value of i = 16
Value of i = 14
Value of i = 12
Value of i = 10
Value of i = 8
Value of i = 6
Value of i = 4
Value of i = 2

for(j <- finish to start){......}

for(j <- finish to start by -1){.......}