Scala的Map集合

 

import scala.collection.mutable
object test27 {
  def main(args: Array[String]): Unit = {

//    //不可变Map
//    val stu1:Map[String,Int]=Map("alice"->90,"bob"->85)
//    //1.添加
//    val  stu1_1=stu1+("小花"->110)
//    println(stu1_1)


    //可变Map
    val stu2=mutable.Map("alice"->90,"abc"->85)
    //1.添加
    stu2+=("小花"->110)
    stu2.put("小明",99)
    println(stu2)
    //2.查询
    //2.1
    val rs=stu2.get("小花1")//找不到，返回None
    //它的得到一个包装对象，具体内容需要再次调用get。 rs。get
    //2.2
    val rs1=stu2("小花1")//找不到，直到报错！
    println(rs.get,rs1)

//3.删除
    stu2.remove("alice")
    stu2-="bob"
//4.遍历
    //4.for循环
    for((k,v)<-stu2){
      println(s"姓名：${k}, 分数：${v}")

    }
    //4.2foreach
    stu2.foreach{case (key,value)=>
    println((s"姓名：${key}，分数：${value}"))
    }
    println(stu2)
  }


}

 

 

 

 

import scala.collection.mutable
object p2 {
  def main(args: Array[String]): Unit = {
    //1
    val books = mutable.Map(
      "001" -> ("西游记","吴承恩","10"),
      "002" -> ("三国演义","罗贯中","11"),
    )
 
    //2
    books += ("003" -> ("书1","作者1","22"))
    books += ("004" -> ("书2","作者2","53"))
    println(books)
 
    //3
    val rs = books.get("001")
    println(rs.get)
 
    //4
    books("001") = ("西游记","吴承恩","88")
    println(books)
 
    //5
    books -= "003"
    println(books)
 
    //6
    for ((k,(v1,v2,v3)) <- books) {
      println(s"${k}的书名为:${v1},作者为:${v2},库存为:${v3}")
    }
  }
}

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