Scala练习

import scala.collection.mutable.ListBuffer
//1.使用 case class 创建图书信息类 Book：
case class Book(ID:String,bookName:String,author:String,price:Double,var amount:Int)
object demo1 {
  def main(args: Array[String]): Unit = {
    //2.创建一个名为 BookList 的可变 List：
    val BookList = ListBuffer[Book]()

    //.3初始化三本不同的书：
    BookList += Book("001","book1","author1",100,10)
    BookList += Book("002","book2","author2",200,20)
    BookList += Book("003","book3","author3",300,30)

    //4.添加一本书
    val book1 = Book("002","b","b2",150,5)
    //如果已经包含这本书，直接去修改数量
    val rs = BookList.find(_.ID == book1.ID)
    if(rs.isEmpty){
      println("没有")
      BookList += book1
    }else{
      println("有")
      val s = rs.get  //拿出具体的数据
      s.amount += book1.amount //数量增加
    }

    //5.根据名称去查询
    var bookName = "book4"
    val rs1 = BookList.find(_.bookName == bookName)
    if(rs1.isEmpty)
      println(s"《$bookName》 不存在")
    else
      println(s"《$bookName》 存在")

    //6.删除指定书名的书
    bookName = "book1"
    val rs2 = BookList.find(_.bookName == bookName)
    if (rs2.isEmpty)
      println(s"《$bookName》 不存在,删除失败")
    else {
      println(s"《$bookName》 存在,删除成功")
      BookList -= rs2.get
    }

    //7.删除指定ID的书
    val ID = "002"
    val rs3 = BookList.find(_.ID == ID)
    if(rs3.isEmpty)
      println(s"id:$ID 不存在,删除失败")
    else {
      println(s"id:$ID 存在,删除成功")
      BookList -= rs3.get
    }

    //8.价格排序
    val orderList = BookList.sortWith((a,b) => a.price>b.price)

    //9.遍历
    orderList.foreach(el =>{
      println(s"书名${el.bookName},作者${el.author},价格${el.price},数量${el.author}")
    })

    //10.计算全部的金额
    var sum:Double = 0;
    BookList.foreach((el =>{
      sum += (el.amount * el.price)
    }))
    println(s"总金额是：${sum}")
  }
}