Scala mutable.Map可变的Map

package chapter07  2 
import scala.collection.mutable  4 
object Test09_MutableMap {  6   def main(args: Array[String]): Unit = {  7     // 1. 创建map
    val map1: mutable.Map[String, Int] = mutable.Map("a" -> 13, "b" -> 25, "hello" -> 3)  9  println(map1) 10  println(map1.getClass) 11 
    println("==========================") 13 
    // 2. 添加元素
    map1.put("c", 5) 16     map1.put("d", 9) 17  println(map1) 18 
    map1 += (("e", 7)) 20  println(map1) 21 
    println("====================") 23 
    // 3. 删除元素
    println(map1("c")) 26     map1.remove("c") 27     println(map1.getOrElse("c", 0)) 28 
    map1 -= "d"
 println(map1) 31 
    println("====================") 33 
    // 4. 修改元素
    map1.update("c", 5) 36     map1.update("e", 10) 37  println(map1) 38 
    println("====================") 40 
    // 5. 合并两个Map
    val map2: Map[String, Int] = Map("aaa" -> 11, "b" -> 29, "hello" -> 5) 43 // map1 ++= map2
 println(map1) 45  println(map2) 46 
    println("---------------------------") 48     val map3: Map[String, Int] = map2 ++ map1 49  println(map1) 50  println(map2) 51  println(map3) 52  } 53 }