Scala的迭代器操作实例

Scala 复制代码
object Test2 {
  //  1. 创建学生信息数据结构和初始数据
  def main(args: Array[String]): Unit = {


    case class Student(name: String, age: Int, scores: List[Int])

    val students = List(
      Student("Alice", 21, List(90, 85, 88)),
      Student("Bob", 19, List(78, 92, 85)),
      Student("Charlie", 22, List(88, 77, 93)),
      Student("David", 20, List(90, 88, 87)),
      Student("Eve", 21, List(76, 85, 92))
    )
    //  创建迭代器并进行基础遍历
    val studentIterator = students.iterator
    while (studentIterator.hasNext) {
      println(studentIterator.next().name)
    }
    //  3. 使用duplicate方法和筛选操作
    val duplicatedIterator = students.iterator
    val ageFiltered = students.filter(_.scores.head > 20) // 假设scores的第一个元素是年龄
    val chineseFiltered = students.filter(_.scores.tail.last > 80) //
    //  4. 使用zip方法关联信息
    val averageScores = students.map(student => student.scores.sum / student.scores.size)
    val zippedIterator = students.iterator.zip(averageScores.iterator)
    while (zippedIterator.hasNext) {
      val (student, avgScore) = zippedIterator.next()
      println(s"${student.name} has an average score of $avgScore")
      //    5. 打印前三名的同学信息
      val topThree = students.take(3)
      topThree.foreach(println)
      //    6. 打印从第4名开始的后3位同学的信息
      val fromFourthToSixth = students.drop(3).take(3)
      fromFourthToSixth.foreach(println)
      //    7. 重新创建学生列表的迭代器
      //    用于统计所有学生的所有成绩的总和
      //    打印结果
      val totalScoresIterator = students.iterator.flatMap(_.scores)
      val totalScores = totalScoresIterator.sum
      println(s"Total scores: $totalScores")

      //    8. 再次使用该迭代器，筛选出成绩列表中有至少一个特定分数以上的学生信息，并打印他们的姓名和年龄
      val highScoreThreshold = 90
      val highScoreStudents = students.filter(_.scores.exists(_ > highScoreThreshold))
      highScoreStudents.foreach(student => println(s"Name: ${student.name}, Age: ${student.age}"))

    }
  }
}