DT大数据梦工厂 第5讲

DT大数据梦工厂 第5讲 http://yun.baidu.com/s/1jGjFpWy 本节王老师讲了数组。最主要的是使用了scala worksheet这个功能。这个功能可以打印出每一行代码的运行情况。 package com.dt.scala.hello

import scala.collection.mutable.ArrayBuffer

object ArrayOps {

  def main(args: Array[String]): Unit = {     val nums = new Array[Int](10)     val a = new Array[String](10)     val s = Array("Hello", "World")     s(0) = "Goodbye"           val b = ArrayBuffer[Int]()     b += 1     b += (1, 2, 3, 5)     b ++= Array(8, 13, 21)     b.trimEnd(5)     b.insert(2, 6)     b.insert(2, 7, 8, 9)     b.remove(2)     b.remove(2, 3)     b.toArray         for (i <- 0 until a.length)      println(i + ": " + a(i))               val c = Array(2, 3, 5, 7, 11)     val result = for (elem <- c) yield 2 * elem     for (elem <- c if elem % 2 == 0) yield 2 * elem     c.filter(_ % 2 == 0).map(2 * _)         Array(1, 7, 2, 9).sum     ArrayBuffer("Mary", "had", "a", "little", "lamb").max         val d = ArrayBuffer(1, 7, 2, 9)     val bSorted = d.sorted         val e = Array(1, 7, 2, 9)     scala.util.Sorting.quickSort(e)         e.mkString(" and ")     a.mkString("<", ",", ">")         val matrix = Array.ofDim[Double](3, 4)     matrix(2)(1) = 42     val triangle = new Array[Array[Int]](10)      for (i <- 0 until triangle.length)      triangle(i) = new Array[Int](i + 1)           }

}