统计成绩练习

1.计算每个同学的总分和平均分

2.统计每个科目的平均分

3.列出总分前三名和单科前三名，并保存结果到文件中

        解题思路如下：

        1.读入txt文件，按行读入

        2.处理数据

        （1）计算每个同学的总分平均分

import scala.collection.mutable.ListBuffer
import scala.io.Source
case class Student(name: String, yuwen: Double, shuxue: Double, yingyu: Double, total: Double, avg: Double)
//案例分析：统计成绩
object Test文件读写_成绩分析 {
  def main(args: Array[String]): Unit = {

    //可变List，保存索引的学生数据
    val studentList = ListBuffer[Student]()

    //1.按行读入
    val source = Source.fromFile("score.txt")
    val it = source.getLines()//迭代器
    it.next()//跳过第一行
    while (it.hasNext){
      val arr = it.next().split(",")//中文的逗号
      val name = arr(0)
      val yuwen = arr(1).toDouble
      val shuxue = arr(2).toDouble
      val yingyu = arr(3).toDouble
      val total = yuwen + shuxue +yingyu //计算总分
      val avg = total / 3  //计算平均分
      //println(name,yuwen,shuxue,yingyu,total,avg)
      val s = Student(name,yuwen,shuxue,yingyu,total,avg)
      studentList +=s
    }
    source.close()

    studentList.foreach(println)

  }
}

        （2）每个科目的平均分

        （3）总分的前三名

        （4）单科的前三名

        3.把结果写入文件

      完整代码如下：

package Scala_CSDN.十一月

import javafx.print.Printer

import java.io.PrintWriter
import scala.collection.mutable.ListBuffer
import scala.io.Source
case class Student(name:String, yuwen:Double, shuxue:Double, yingyu:Double, total:Double, avg:Double)
object 统计成绩 {
  def main(args: Array[String]): Unit = {
    //可变List，保存所有的学生数据
    val studentList = ListBuffer[Student]()
    //1.按行读入文件
    val source = Source.fromFile("score.txt")
    val it = source.getLines() //迭代器
    it.next()//跳过第一行
    while (it.hasNext){
      val arr = it.next().split("，")//中文逗号
      val name = arr(0)
      val yuwen = arr(1).toDouble
      val shuxue = arr(2).toDouble
      val yingyu = arr(3).toDouble
      val total = yuwen + shuxue + yingyu //计算总分
      val avg = total / 3  //计算平均分
      val s = Student(name, yuwen, shuxue, yingyu, total, avg)
      studentList += s
    }
    source.close()
    //计算单科总分
    var avgyuwen:Double = 0
    var avgshuxue:Double = 0
    var avgyingyu:Double = 0
    studentList.foreach(s=>{
      avgyuwen += s.yuwen
      avgshuxue += s.shuxue
      avgyingyu += s.yingyu
    })
    println("语文平均分",avgyuwen / studentList.length)
    println("数学平均分",avgyuwen / studentList.length)
    println("英语平均分",avgyuwen / studentList.length)
    //总分的前三名
    //思路：1.对所有的同学按总分从高到低排名
    val list1 = studentList.sortWith((a,b)=>a.total > b.total).slice(0,3)
    println("总分从高到低排名前三：")
    list1.foreach(println)
    //单科的前三名
    val list2 = studentList.sortWith((a,b)=>a.yuwen > b.yuwen).slice(0,3)
    println("语文从高到低排名前三：")
    list2.foreach(println)
    val list3 = studentList.sortWith((c,d)=>c.shuxue > d.shuxue).slice(0,3)
    println("数学从高到低排名前三：")
    list3.foreach(println)
    val list4 = studentList.sortWith((c,d)=>c.yingyu > d.yingyu).slice(0,3)
    println("英语从高到低排名前三：")
    list4.foreach(println)
    //写入文件
    val writer = new PrintWriter("统计成绩的结果")
    writer.println("姓名，语文成绩，数学成绩，英语成绩，总分，平均分")
    studentList.foreach(s=>{
      val avg = f"${s.avg}%.1f" //只保留一位有效数字
      writer.println(s"${s.name},${s.yuwen},${s.shuxue},${s.yingyu},${s.total},${avg}")
    })
    writer.println("-"*40)
    //总分前三名
    list1.foreach(s=>{
      val avg = f"${s.avg}%.1f"
      writer.println(s"${s.name},${s.yuwen},${s.shuxue},${s.yingyu},${s.total},${avg}")
    })
    writer.println("-"*40)
    //语文前三名
    list2.foreach(s=>{
      val avg = f"${s.avg}%.1f" //只保留一位有效数字
      writer.println(s"${s.name},${s.yuwen},${s.shuxue},${s.yingyu},${s.total},${avg}")
    })
    writer.println("-"*40)
    //英语前三名
    list3.foreach(s=>{
      val avg = f"${s.avg}%.1f" //只保留一位有效数字
      writer.println(s"${s.name},${s.yuwen},${s.shuxue},${s.yingyu},${s.total},${avg}")
    })
    writer.println("-"*40)
    //数学前三名
    list4.foreach(s=>{
      val avg = f"${s.avg}%.1f" //只保留一位有效数字
      writer.println(s"${s.name},${s.yuwen},${s.shuxue},${s.yingyu},${s.total},${avg}")
    })
    writer.println("-"*40)
    writer.close()  //关闭文件
  }
}

身份证查询籍贯

根据身份证号码前两位，输出其所属籍贯：

     eg：42湖北，33浙江，11北京，31上海

object Test_身份证查询籍贯 {
  def main(args: Array[String]): Unit = {
    val code = "42005200210030051".substring(0,2)
    println(code)
    //判断42是哪个省的
    //湖北
//    if(code == "42"){
//      println("42对应省份为：湖北")
//    }else if(code =="33"){
//      println("浙江")
//    }else{
//      println()
//    }
 
    val province = code match {
      case "11" => "北京"
      case "12" => "天津"
      case "13" => "河北"
      case "14" => "山西"
      case "15" => "内蒙古"
      case "21" => "辽宁"
      case "22" => "吉林"
      case "23" => "黑龙江"
      case "31" => "上海"
      case "32" => "上海"
      case "33" => "浙江"
      case "34" => "安徽"
      case "35" => "福建"
      case "36" => "江西"
      case "37" => "山东"
      case "41" => "河南"
      case "42" => "湖北"
      case "43" => "湖南"
      case "44" => "广东"
      case "45" => "广西"
      case "46" => "海南"
      case "50" => "重庆"
      case "51" => "四川"
      case "52" => "贵州"
      case "53" => "云南"
      case "54" => "西藏"
      case "61" => "陕西"
      case "62" => "甘肃"
      case "63" => "青海"
      case "64" => "宁夏"
      case "65" => "新疆"
      case "71" => "台湾"
      case "81" => "香港"
      case "82" => "澳门"
      case "91" => "国外"
      case "_" => "未知"
    }
    println(province)
  }
}

根据输出的数字输出对应 的星期的英文

算出正方形，长方形，梯形面积