1.编写一段代码，将a设置为一个n个随机整数的数组，要求随机数介于0（包含）和n（不包含）之间
/**
* Created by vito on 2017/1/11.
*/
object ex1 {
def main(args: Array[String]): Unit = {
//从键盘获得输入
val n = readInt()
val array = new Array[Int](n)
for (i <- 0 until array.length) {
array(i) = (new util.Random).nextInt(n)
}
println(array.mkString(","))
}
}
2.编写一个循环，将整数数组中相邻的元素置换。例如，Array（1,2,3,4,5）经过置换后变为Array（2,1,4,3,5）
/**
* Created by vito on 2017/1/11.
*/
object ex2 {
def main(args: Array[String]): Unit = {
val array = Array(1,2,3,4,5) //将步进设置为2
for (i <- 0 until (array.length, 2)) {
if (i != array.length - 1) {
val tmp = array(i)
array(i) = array(i + 1)
array(i + 1) = tmp
}
}
println(array.mkString(","))
}
}
3.重复前一个练习，不过这一次生成一个新的值交换过的数组。用for/yield。
/**
* Created by vito on 2017/1/11.
*/
object ex3 {
def main(args: Array[String]): Unit = {
val array = Array(1, 2, 3, 4, 5) val newArray = for (i <- 0 until(array.length)) yield {
if (i != array.length - 1) {
if (i % 2 == 0) array(i + 1) else array(i - 1)
} else {
array(i)
} } println(newArray.mkString(","))
}
}
4.如何计算Array[Double]的平均值？
/**
* Created by vito on 2017/1/11.
*/
object ex5 {
def main(args: Array[String]): Unit = {
val array = Array(1, 2, 3, 4, 5) val avg = array.sum / array.length println(avg)
}
}
5.创建一个二维数组，将其中一维数组的顺序逆序，并将每个一维数组中的值逆序。
scala> val dim = List(List(1,2,3), List(1,2,3,4), List(1,2,3,4,5))
dim: List[List[Int]] = List(List(1, 2, 3), List(1, 2, 3, 4), List(1, 2, 3, 4, 5)) scala> dim.map(_.reverse).reverse
res11: List[List[Int]] = List(List(5, 4, 3, 2, 1), List(4, 3, 2, 1), List(3, 2, 1))