Scala-List

//列表拼接
    List("a","b"):::List("c","d") //List(a,b,c,d)
    List("a","b")++List("c","d")    //List(a,b,c,d)
    List("a","b")++:List("c","d")   //List(a,b,c,d)
    List("a","b")::List("c","d")    //List(List(a, b), c, d)
    List("a","b"):+List("c","d")    //List(a, b, List(c, d))
	//列表长度  length
    List("a","b").length //2
    //****************************
    val fList=List("apple","banana","orange")
	//最后一个元素
    fList.last  //orange
    //除最后一个元素外所有元素
    fList.init  //List("apple","banana")
	//反转
    fList.reverse   //List("orange","banana","apple")
    //取前n个元素
    fList.take(2)   //List("orange","banana")
    //取第n个元素(从0开始)
    fList.apply(2)  //orange
    fList(2)
    //修改第n个元素
    fList.updated(2,"orange2")   //List("apple","banana","orange2")
    //从第n分成两个表
    fList.splitAt(1)    //(List("apple"),List("banana","orage"))
    //除去前n个元素
    fList.drop(2)   //List("orange")
	//***************************************
	val test = List('a','b','c','d','e')
	//元素的索引
    test.indices    //Range(0, 1, 2, 3, 4)
    //索引和元素组成的元组
    test.indices zip test   //Vector((0,a), (1,b), (2,c), (3,d), (4,e))
    //元素和索引组成的List
    test.zipWithIndex   //List((a,0), (b,1), (c,2), (d,3), (e,4))
	//mkString分割
    test.mkString   //abcde
    test.mkString("#")  //a#b#c#d#e
    test.mkString("[","|","]")  //[a|b|c|d|e]
    //grouped分组
    test.grouped(2).mkString(",")   // List(a, b),List(c, d),List(e)
	//************************
    //遍历
    data.foreach{x=>print(x+",")}   //a,b,c,d,e,
    data.map{x=>print(x+",")}   //a,b,c,d,e,