scala基本语法

1.if2.Array和ArrayBuffera）Array：不带原始值的需要newb）ArrayBuffer：需要导包c）Array的方法 3.for循环遍历数组to和until

1.if

val a = 20 val aResult = if(a > 10){ 10 }else{ 30 } println(aResult) // 输出结果为10 val b = 20 val bResult = if(b > 10){ "hello" }else{ 30 } println(aResult) //输出hello

2.Array和ArrayBuffer

a）Array：不带原始值的需要new

scala> val a = new Array[Int](4) //中括号表示元素类型，小括号表示数元素个数 scala> a(1) = 2 scala> a res16: Array[Int] = Array(0, 2, 0, 0) -------------------------------------- scala> val a1 = Array[Int](1,2,3,4) a1: Array[Int] = Array(1, 2, 3, 4)

b）ArrayBuffer：需要导包

scala> import scala.collection.mutable.ArrayBuffer import scala.collection.mutable.ArrayBuffer //因为是可变数组，所以不需要设定元素个数 scala> val a2 = new ArrayBuffer[Int] a2: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer() //追加元素采用append方法 scala> a2.append(12,11,23,45) 或 a2 += scala> a2 res12: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(12, 11, 23, 45) //移除元素用remove方法，括号里面为元素的索引 scala> a2.remove(0) 或 a2 -= res18: Int = 12 scala> a2 res19: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(12, 23, 45)

c）Array的方法

scala> a2.sum res31: Int = 80 scala> a2.max res32: Int = 45 scala> a2.sorted res33: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(12, 23, 45) scala> a2.sorted.reverse //反序 res3: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(45, 23, 12) //将排序后的数组遍历打印 val a3 =a2.sorted for(i <- 0 until a3.size) println(a3(i)) 12 23 45

3.for循环遍历数组

scala> for(a <- a2 ) println(a) 12 23 45 scala> for(i <- 0 until a2.size) println(a2(i)) 12 23 45

to和until

to是含头又含尾 until是含头不含尾