创建列表

scala> val days = List("Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday")days: List[String] = List(Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday)

创建空列表

scala> val l = Nill: scala.collection.immutable.Nil.type = List() scala> val l = List()l: List[Nothing] = List()

用字符串创建列表

scala> val l = "Hello" :: "Hi" :: "Hah" :: "WOW" :: "WOOW" :: Nill: List[String] = List(Hello, Hi, Hah, WOW, WOOW)

用“:::”叠加创建新列表

scala> val wow = l ::: List("WOOOW", "WOOOOW")wow: List[String] = List(Hello, Hi, Hah, WOW, WOOW, WOOOW, WOOOOW)

通过索引获取列表值

scala> l(3)res0: String = WOW

获取值长度为3的元素数目

scala> l.count(s => s.length == 3)res1: Int = 2

返回去掉l头两个元素的新列表

scala> l.drop(2)res2: List[String] = List(Hah, WOW, WOOW) scala> lres3: List[String] = List(Hello, Hi, Hah, WOW, WOOW)

返回去掉l后两个元素的新列表

scala> l.dropRight(2)res5: List[String] = List(Hello, Hi, Hah) scala> lres6: List[String] = List(Hello, Hi, Hah, WOW, WOOW)

判断l是否存在某个元素

scala> l.exists(s => s == "Hah")res7: Boolean = true

滤出长度为3的元素

scala> l.filter(s => s.length == 3)res8: List[String] = List(Hah, WOW)

判断所有元素是否以“H”打头

scala> l.forall(s => s.startsWith("H"))res10: Boolean = false

判断所有元素是否以“H”结尾

scala> l.forall(s => s.endsWith("W"))res11: Boolean = false

打印每个元素

scala> l.foreach(s => print(s + ' '))Hello Hi Hah WOW WOOW

取出第一个元素

scala> l.headres17: String = Hello

取出最后一个元素

scala> l.lastres20: String = WOOW

剔除最后一个元素，生成新列表

scala> l.initres18: List[String] = List(Hello, Hi, Hah, WOW)

剔除第一个元素，生成新列表

scala> l.tailres49: List[String] = List(Hi, Hah, WOW, WOOW)

判断列表是否为空

scala> l.isEmptyres19: Boolean = false

获得列表长度

scala> l.lengthres21: Int = 5

修改每个元素，再反转每个元素形成新列表

scala> l.map(s => {val s1 = s + " - 01"; s1.reverse})res29: List[String] = List(10 - olleH, 10 - iH, 10 - haH, 10 - WOW, 10 - WOOW)

生成用逗号隔开的字符串

scala> l.mkString(", ")res30: String = Hello, Hi, Hah, WOW, WOOW

反序生成新列表

scala> l.reverseres41: List[String] = List(WOOW, WOW, Hah, Hi, Hello)

按字母递增排序

scala> l.sortWith(_.compareTo(_) < 0)res48: List[String] = List(Hah, Hello, Hi, WOOW, WOW)