创建map

scala> val map = Map("name"->"erhuan","age"->20) map: scala.collection.immutable.Map[String,Any] = Map(name -> erhuan, age -> 20) //等效于 scala> val map = Map(("name","erhuan"),("age"->20)) map: scala.collection.immutable.Map[String,Any] = Map(name -> erhuan, age -> 20)

创建可变map

scala> val map = scala.collection.mutable.Map("name"->"erhuan","age"->20) map: scala.collection.mutable.Map[String,Any] = Map(age -> 20, name -> erhuan)

获取map中的值

scala> val name=map("name") name: Any = erhuan //查看map是否包含某个key scala> if(map.contains("name")) map("name") res0: Any = erhuan

更新map

//更新值 scala> map("name")="lilin" scala> map res2: scala.collection.mutable.Map[String,Any] = Map(age -> 20, name -> lilin) //添加键值对 scala> map+=("tall"->1.5) res4: map.type = Map(tall -> 1.5, age -> 20, name -> lilin) //删除键值对 scala> map-=("tall") res5: map.type = Map(age -> 20, name -> lilin)

其他操作

// 遍历所有 scala> for((k,v)<-map){println(k+"="+name)} age=erhuan name=erhuan //便利key scala> map.keySet res10: scala.collection.Set[String] = Set(age, name) //遍历values scala> for(v <-map.values) println(v) 20 lilin // k v反转 scala> for((k,v)<-map) yield(v,k) res12: scala.collection.mutable.Map[Any,String] = Map(20 -> age, lilin -> name)