list

scala集合有三大类，序列Seq,集合Set，映射Map

package chapter03
import scala.collection.immutable
import scala.collection.mutable
import scala.collection.mutable.ListBuffer

//scala默认采用不可变集合
//scala集合有三大类，序列Seq,集合Set，映射Map

object test02 {
  def main(args:Array[String]):Unit={

    //TODO 不可变集合
    var list:List[Int]=List(1,2,3,4)

    //查找数据;索引
    println(list(0))

    //添加元素
    var list1:List[Int]=list:+ 6
    var list2:List[Int]=7+:list
    println(list1.mkString(","))//1,2,3,4,6
    println(list2.mkString(","))//7,1,2,3,4

    //添加类表
    var list3:List[Int]=list++ (list1)
    println(list3.mkString(","))  //1,2,3,4,1,2,3,4,6

    var list4:List[Int]=list.::(9)
    println(list4.mkString(",")) //9,1,2,3,4

    //先算后面
    var list5:List[Int]=7::8::9::list
    println(list5.mkString(",")) //7,8,9,1,2,3,4

    var list6:List[Int]=9::list1:::list
    println(list6.mkString(",")) //7,8,9,1,2,3,4

    //特殊List;Nil
    println(List()) //List()
    println(Nil)//List()

    //修改
    var list7:List[Int]=list.updated(2,5)
    println(list7.mkString(","))//1,2,5,4

    //删除数据:个数
    var list8:List[Int]=list.drop(10)
    println(list8.mkString(","))//1,2,5,4

    //TODO 可变集合
    var mlist=ListBuffer(5,6,7,8)

    //mlist.insert()
    //mlist.updated()
    //mlist.drop()
    //mlist.remove()

    //属性
    println(mlist.head) //5
    println(mlist.last) //8

    println(mlist.init)//ListBuffer(5, 6, 7)
    println(mlist.tail)//ListBuffer(6, 7, 8)

    //队列:一定是可变的
    var q=mutable.Queue(1,2,3,4)

    //添加数据
    q.enqueue(5)
    println(q) //Queue(1, 2, 3, 4, 5)

    //删除数据
    var i:Int=q.dequeue()
    println(i) //1
    println(q) //Queue(2, 3, 4, 5)







  }

}