import collection.mutable.Buffer

object CollectionDemo6 {

  def main(args: Array[String]): Unit = {

    //可变集合类型推导

    val nums = Buffer(1)

    for (i <- 2 to 10) nums += i

    println(nums)

    //可变集合类型定义

    val nums2 = Buffer[Int]()

    for (i <- 1 to 10) nums2 += i

    println(nums2)

    //可变转不可变集合

    println(nums2.toList)

    //不可变转可变

    val m = Map("a" -> 1, "b" -> 2)

    println(m.toBuffer)

    //newBuilder 构建可变集合，result转为不可变集合，但是构造器知道可变集合的类型。

    val ls = List.newBuilder[String]

    ls ++= List("a", "b", "c")

    println(ls.result())

  }

}