scala集合類型： map-reduce

1. scala複雜數據類型的基本使用
2. 類，對象，函數： class,object, def …
3. scala集合：模擬map-reduce

part1: scala 數組/集合基礎

	Array	List，Set	Map	Tuple1…20
創建容器	Array(1,2,3)	List(1,2,3) / Array(1,2,3).toList	Map(“k1”->“1”,“k2”->“2”)	scala.Tuple3(1,2,3)/ (1,2,3)
取出元素	arr(0), arr(1)	list(0),list(1)	map(“k1”)	tup._1, tup._2
常用函數	size, sum,min, max,toList, flatMap	sortBy,reverse,toMap,flatMap,groupBy,reduce	map,mapValues,groupBy,filter

part2: class,object,函數

函數

//for循環
for(i<-1 to 9){
	for(j <-1 to 9){
		if(i>=j){
			printf("%d * %d = %d \t", j,i,(j*i))
		}
	}
	println()
}

import scala.util.control.Breaks._
for(i<- 1 to 9; j<- 1 to 9){
	if(i>=j){
		printf("%d * %d = %d \t", j,i,(j*i))
	}else {
		if(j>i) {println() ; return}
	}
}
for(i<-"hello"){
	println(i)
}

//while循環
var x=5
while( x>0){
	println(x)
	x-=1
}

//線程調用
def thread(  f:()=>Unit )={
	new Thread(){
		override def run()={
			f()
		}
	}.start()
}
def f ={
	while(true)
		println("a")
		Thread.sleep(100)
}
thread(() => println("hello"))

//求解： 直線方程
def f( x1:Int,y1:Int,  x2:Int, y2:Int ):Int=>Int = {

	k=(y2-y1)/(x2-x1)
	b=y1-k*x1

	def fun(x:Int)={
		k*x+b
	}
	fun _
}
f(1,2,3,4)(5)

part3: 類，對象，函數

//類
class Person(var name:String, var age:Int) {
  //重寫構造
  def this(){
    this("lisi",23)
  }
  //自動生產： get,set
}
//類：伴生對象--單例模式：靜態方法
object Person{
  def sayHello(p:Person ): Unit ={
    println(p.name+","+p.age)
  }
}
//啓動入口===============================
object AppTest{
  def main(args: Array[String]): Unit = {
    Person.sayHello(new Person())//lisi,23
  }
}