问将文件和存储元素读取为数组Scala

EN

    val lines = Source.fromFile("columns").getLines() 
    /* gets an Iterator[String] which interfaces a collection of all the lines in the file*/
    val linesAsArraysOfInts = lines.map(line => line.split(" ").map(_.toInt)) 
    /* Here you transform (map) any line to arrays of Int, so you will get as a result an Interator[Array[Int]] */ 
    val pair: (List[Int], List[Int]) = linesAsArraysOfInts.foldLeft((List[Int](), List[Int]()))((acc, cur) => (cur(0) :: acc._1, cur(1) :: acc._2))
    /* The foldLeft method on iterators, allows you to propagate an operation from left to right on the Iterator starting from an initial value and changing this value over the propagation process. In this case you start with two empty Lists stored as Tuple an on each step you prepend the first element of the array to the first List, and the second element to the second List. At the end you will have to Lists with the columns in reverse order*/

    val leftList: List[Int] = pair._1.reverse
    val rightList: List[Int] = pair._2.reverse
    //finally you apply reverse to the lists and it's done :)

val file: String = ??? // path to .txt in String format
val source = Source.fromFile(file)

scala> val columnsTogether = source.getLines.map { line =>
  val nums = line.split(" ") // creating an array of just the 'numbers'
  (nums.head, nums.last) // assumes every line has TWO numbers only
}.toList
columnsTogether: List[(String, String)] = List((1,2), (2,3), (3,4), (4,5), (1,6), (6,7), (7,8), (8,9), (6,10))

scala> columnsTogether.map(_._1.toInt)
res0: List[Int] = List(1, 2, 3, 4, 1, 6, 7, 8, 6)

scala> columnsTogether.map(_._2.toInt)
res1: List[Int] = List(2, 3, 4, 5, 6, 7, 8, 9, 10)