场景
数组的语法与使用
实验
package com.scode.scala
import scala.collection.mutable.ArrayBuffer
/**
* author: Ivy Peng
* function: 数组操作实战详解
* date:2016/02/22 22.37
* sum：
* Eclipse worksheet具有实时初步编译的功能，相当好用啊
*/
object ArraysInAction
{
println("Welcome to the Scala worksheet") //> Welcome to the Scala worksheet
/**
* 数组的定义 语法:
* new [Array|ArrayBuffer][DType](size)
*/
val nums = new Array[Int](10) //> nums : Array[Int] = Array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
val strs = new Array[String](10) //> strs : Array[String] = Array(null, null, null, null, null, null, null, null
//| , null, null)
val s = Array("Hello","World") //> s : Array[String] = Array(Hello, World)
s(0) = "Good Bye"
/**
* 数组的基本操作 与 遍历
* 语法： arrayName(i)
*/
val b = ArrayBuffer[Int]() //> b : scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer()
b+=1 //> res0: com.scode.scala.ArraysInAction.b.type = ArrayBuffer(1)
b+=(1,2,3,5) //> res1: com.scode.scala.ArraysInAction.b.type = ArrayBuffer(1, 1, 2, 3, 5)
b++=Array(3,5,5) //> res2: com.scode.scala.ArraysInAction.b.type = ArrayBuffer(1, 1, 2, 3, 5, 3,
//| 5, 5)
b.trimEnd(3)
b.insert(0, 99)
b.remove(0) //> res3: Int = 99
b.insert(0, 2,22,222)
b.remove(2, 3)
b.toArray //> res4: Array[Int] = Array(2, 22, 2, 3, 5)
for(i <- 0 until b.length)
{
println(i +":" + b(i)) //> 0:2
//| 1:22
//| 2:2
//| 3:3
//| 4:5
}
/**
* 数组的高级操作 与 多维数组
*/
val c = Array(2,3,58) //> c : Array[Int] = Array(2, 3, 58)
val result = for(elem <- c) yield elem*3 //> result : Array[Int] = Array(6, 9, 174)
for(elem <- c if elem % 2 == 0) yield elem*2 //> res5: Array[Int] = Array(4, 116)
c.filter(_%2 == 0).map(2*_) //> res6: Array[Int] = Array(4, 116)
Array(1,2,3).sum //> res7: Int = 6
ArrayBuffer("Ivy","Daisy","Shasha").max //> res8: String = Shasha
val d = ArrayBuffer(1,2,7,9) //> d : scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(1, 2, 7, 9)
val dSorted = d.sorted //> dSorted : scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(1, 2, 7,
//| 9)
val e = Array(1,3,5,3,4) //> e : Array[Int] = Array(1, 3, 5, 3, 4)
scala.util.Sorting.quickSort(e)
e.mkString(" and ") //> res9: String = 1 and 3 and 3 and 4 and 5
e.mkString("{", ":", "}") //> res10: String = {1:3:3:4:5}
//多维数组
val matrix = Array.ofDim[Double](3, 4) //> matrix : Array[Array[Double]] = Array(Array(0.0, 0.0, 0.0, 0.0), Array(0.0
//| , 0.0, 0.0, 0.0), Array(0.0, 0.0, 0.0, 0.0))
matrix(2)(1)= 42
val triangle = new Array[Array[Int]](10) //> triangle : Array[Array[Int]] = Array(null, null, null, null, null, null, n
//| ull, null, null, null)
for(i <- 0 until triangle.length)
{
triangle(i) = new Array[Int](i+1)
}
}
参考文献
scala 深入浅出实战经典 . 王家林
