Array基本操作

 1 // defined array object
 2     val arr0= new Array[String](10)
 3     val arr1= Array("Hello","1")
 4     println(arr1(0))
 5     arr1(0)="Hello Spark!"
 6     println(arr1(0))
 7     // array's length can't change,but ArrayBuffer can.
 8 
 9     val arr2= ArrayBuffer(1)
10     arr2+=1
11     for(item <- arr2) println(item)
12     arr2+=(2,3,4,5)
13     println(arr2.mkString(","))
14     arr2++=Array(6,7,8)
15     println(arr2.mkString(","))
16     arr2.trimEnd(5)
17     println(arr2.mkString(","))
18     arr2.insert(2,6)
19     println(arr2.mkString(","))
20     arr2.insert(2,5,5,6)
21     println(arr2.mkString(","))
22     arr2.remove(5)
23     println(arr2.mkString(","))
24     arr2.remove(1,4)
25     println(arr2.mkString(","))
26     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

 1 val arr3=Array(1,2,3,4,5,6)
 2     for(i<-0 until arr3.length) println(i+":"+arr3(i))
 3     for(elem<-arr3) println(elem)
 4 
 5     val result= for(elem<-arr3) yield 2*elem;
 6     println(result.mkString(","))
 7     var result0 = for(elem<-arr3 if elem%2==0) yield 2*elem;
 8     println(result0.mkString(","))
 9     println(arr3.filter(_%2==0).map(2*_).mkString(","))
10 
11     println(arr3.sum)
12     val arr4= Array(5,3,10,1,3)
13     val result3= scala.util.Sorting.quickSort(arr4)
14     println(arr4.mkString("<",",",">"))
15 
16     val arr5=ArrayBuffer(1,3,4,10,0,4,5)
17     println(arr5.sorted.mkString(","))
18 
19     val matrix= Array.ofDim[Double](3,4)
20     for(i<- 0 to 2;j<- 0 to 3) println("matrix("+i+")("+j+"):"+matrix(i)(j))
21     matrix(1)(1)=23
22     for(i<- 0 to 2;j<- 0 to 3) println("matrix("+i+")("+j+"):"+matrix(i)(j))
23     var triangle= new Array[Array[Int]](10)
24     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