Array基本操作

// defined array object
    val arr0= new Array[String](10)
    val arr1= Array("Hello","1")
    println(arr1(0))
    arr1(0)="Hello Spark!"
    println(arr1(0))
    // array's length can't change,but ArrayBuffer can.

    val arr2= ArrayBuffer(1)
    arr2+=1
    for(item <- arr2) println(item)
    arr2+=(2,3,4,5)
    println(arr2.mkString(","))
    arr2++=Array(6,7,8)
    println(arr2.mkString(","))
    arr2.trimEnd(5)
    println(arr2.mkString(","))
    arr2.insert(2,6)
    println(arr2.mkString(","))
    arr2.insert(2,5,5,6)
    println(arr2.mkString(","))
    arr2.remove(5)
    println(arr2.mkString(","))
    arr2.remove(1,4)
    println(arr2.mkString(","))
    println(arr2.toArray.mkString(","))

输出结果：

Hello
Hello Spark!
1
1
1,1,2,3,4,5
1,1,2,3,4,5,6,7,8
1,1,2,3
1,1,6,2,3
1,1,5,5,6,6,2,3
1,1,5,5,6,2,3
1,2,3
1,2,3

Process finished with exit code 0

val arr3=Array(1,2,3,4,5,6)
    for(i<-0 until arr3.length) println(i+":"+arr3(i))
    for(elem<-arr3) println(elem)

    val result= for(elem<-arr3) yield 2*elem;
    println(result.mkString(","))
    var result0 = for(elem<-arr3 if elem%2==0) yield 2*elem;
    println(result0.mkString(","))
    println(arr3.filter(_%2==0).map(2*_).mkString(","))

    println(arr3.sum)
    val arr4= Array(5,3,10,1,3)
    val result3= scala.util.Sorting.quickSort(arr4)
    println(arr4.mkString("<",",",">"))

    val arr5=ArrayBuffer(1,3,4,10,0,4,5)
    println(arr5.sorted.mkString(","))

    val matrix= Array.ofDim[Double](3,4)
    for(i<- 0 to 2;j<- 0 to 3) println("matrix("+i+")("+j+"):"+matrix(i)(j))
    matrix(1)(1)=23
    for(i<- 0 to 2;j<- 0 to 3) println("matrix("+i+")("+j+"):"+matrix(i)(j))
    var triangle= new Array[Array[Int]](10)
    for(i<-0 until(triangle.length)) triangle(i)= new Array[Int](i+1)

0:1
1:2
2:3
3:4
4:5
5:6
1
2
3
4
5
6
2,4,6,8,10,12
4,8,12
4,8,12
21
<1,3,3,5,10>
0,1,3,4,4,5,10
matrix(0)(0):0.0
matrix(0)(1):0.0
matrix(0)(2):0.0
matrix(0)(3):0.0
matrix(1)(0):0.0
matrix(1)(1):0.0
matrix(1)(2):0.0
matrix(1)(3):0.0
matrix(2)(0):0.0
matrix(2)(1):0.0
matrix(2)(2):0.0
matrix(2)(3):0.0
matrix(0)(0):0.0
matrix(0)(1):0.0
matrix(0)(2):0.0
matrix(0)(3):0.0
matrix(1)(0):0.0
matrix(1)(1):23.0
matrix(1)(2):0.0
matrix(1)(3):0.0
matrix(2)(0):0.0
matrix(2)(1):0.0
matrix(2)(2):0.0
matrix(2)(3):0.0

Process finished with exit code 0