定长数组scala> val arr1 = new Array[String](8)arr1: Array[String] = Array(null, null, null, null, null, null, null, null)scala> arr1res5: Array[String] = Array(null, null, null, null, null, null, null, null)scala> println(arr1)[Ljava.lang.String;@1254a3cdscala> println(arr1.toBuffer)ArrayBuffer(null, null, null, null, null, null, null, null)scala> val arr2 = Array("java", "scala", "python")arr2: Array[String] = Array(java, scala, python)scala> println(arr2(0))java边长数组scala> val arr3 = ArrayBuffer[Int]()scala> arr3 +=1scala> arr3 ++= Array(5,6)scala> arr3 ++= ArrayBuffer(7,8)#在0的位置加入-1scala> arr3.insert(0, -1)#在第2的位置，加入2scala> arr3.remove(2,2)scala> val arr = Array(1,2,3,4,5,6,7,8,9)arr: Array[Int] = Array(1, 2, 3, 4, 5, 6, 7, 8, 9)scala> for(i <- arr) println(i)#遍历数组for(i <- 0 until arr.length) println(i)for(i <- (0 until arr.length).reverse) println(i)#把原来数组的值重新计算，生成一个新的数组scala> val res = for(i <- arr) yield i* 10res: Array[Int] = Array(10, 20, 30, 40, 50, 60, 70, 80, 90)#数组所有的和scala> arr.sumres22: Int = 45#数组中最大的值scala> arr.maxres23: Int = 9数组排序scala> arr.sorted#数组相加scala> val arr4 = arr2 ++ arr3arr4: Array[Int] = Array(24, 25, 255, 2, 21, 253)数据类型（元组）

scala> val t = ("scala",1,3.14,("spark",1))t: (String, Int, Double, (String, Int)) = (scala,1,3.14,(spark,1))#取元组里面第一个值，（元组下标从1开始的）scala> t._1res29: String = scala#array 转成mapscala> val arr = Array(("t",2),("n",3),("x",4))arr: Array[(String, Int)] = Array((t,2), (n,3), (x,4))scala> arr.toMapres30: scala.collection.immutable.Map[String,Int] = Map(t -> 2, n -> 3, x -> 4)#拉链操作，把2个Array转成元组scala> val arr1 = Array("tingting","c","d")arr1: Array[String] = Array(tingting, c, d)scala> val arr2 = Array(24,25,255)arr2: Array[Int] = Array(24, 25, 255)scala> arr1 zip arr2res31: Array[(String, Int)] = Array((tingting,24), (c,25), (d,255))import scala.collection.immutable.HashSetval set1 = new HashSet[Int]()val set2 = set1 +12个set组合成一个新的setval set3 = set2 ++ Set(2,3,4)#操作set，增加/删除元素set1 += 1set1 -= 4数据类型（Map)

scala> val map2 = Map(("scala",1), ("java",2), ("python",3))map2: scala.collection.immutable.Map[String,Int] = Map(scala -> 1, java -> 2, python -> 3)scala> val map1 = Map("scala"->1,"java"->2, "python"->3)map1: scala.collection.immutable.Map[String,Int] = Map(scala -> 1, java -> 2, python -> 3)scala> map1("scala")res25: Int = 1# 可变mapscala> import scala.collection.mutable._import scala.collection.mutable._scala> val map1 = Map("scala"->1,"java"->2, "python"->3)map1: scala.collection.mutable.Map[String,Int] = HashMap(python -> 3, java -> 2, scala -> 1)scala> map1("scala") = 6scala> map1.getOrElse("c#", -1)res28: Int = -1import scala.collection.mutable._val map1 = new HashMap[String, Int]()往里面增加数据：map1("scala") = 1map1 += (("java",2))map1 += (("python",3),("C#",4))map1.put("C++",6)减少数据：map1 -="java"map1.remove("scala")数据类型（List)

//生成一个list val list0 = List(2,6,7,4,5,7,8,3,0,1) //将list0中每个元素乘以2后生成一个新的集合 val list1 = list0.map(_ * 2) //将list0中的偶数取出来生成一个新的集合 val list2 = list0.filter(_ % 2 ==0) //将list0排序后生成一个新的集合 val list3 = list0.sorted //反转排序顺序 val list4 = list3.reverse //将list0中的元素4个一组，类型为Iterator[List[Int]] val it = list0.grouped(4) //将Iterator转换成List val list5 = it.toList //将多个list压扁成一个list val list6 = list5.flatten //先按空格切分，再压平 val lines = List("hello java hello scala", "hello scala") //方法一： val words = lines.map(_.split(" ")) val flatWords = words.flatten //方法二： val res = lines.flatMap(_.split(" ")) //并行计算求和 val arr = Array(1,2,3,4,5,6,7,8,9) val res1 = arr.sum //并发// val res2 = arr.par.sum val res2 = (arr).sum //按照特定的顺序进行聚合 val res3 = arr.reduce(_+_) //聚合多维数组 val list7 = List(List(1,2,3)) //求交集 val res4 = list1 intersect list2 //求差集 val res5 = list1 intersect(list2)