scala读书笔记（二）

 val x = List[Number](1, 2.0, 33D, 400L)

val v = Vector("a", "b", "c")                     //> v  : scala.collection.immutable.Vector[String] = Vector(a, b, c)
//IndexedSeq的默认实现
val x = IndexedSeq(1,2,3)                         //> x  : IndexedSeq[Int] = Vector(1, 2, 3)

import scala.collection.mutable.ArrayBuffer
var nums = ArrayBuffer(1, 2, 3)                   //> nums  : scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(1, 2, 3)

val x = Vector(1, 2, 3)                           //> x  : scala.collection.immutable.Vector[Int] = Vector(1, 2, 3)
x.foreach((i: Int) => println(i))                 //> 1
                                                  //| 2
                                                  //| 3

val fruits = Traversable("apple", "banana", "orange")
                                                  //> fruits  : Traversable[String] = List(apple, banana, orange)
for (f <- fruits) println(f)                      //> apple
                                                  //| banana
                                                  //| orange


//使用循环计数器
val fruits = Vector("apple", "banana", "orange")  //> fruits  : scala.collection.immutable.Vector[String] = Vector(apple, banana, o
                                                  //| range)
for (i <- 0 until fruits.size) println(s"element $i is ${fruits(i)}")
                                                  //> element 0 is apple
                                                  //| element 1 is banana
                                                  //| element 2 is orange

val fruits = Vector("apple", "banana", "orange")  //> fruits  : scala.collection.immutable.Vector[String] = Vector(apple, banana, o
                                                  //| range)

fruits.zipWithIndex.foreach{case(e,i)=>println(s"index id $i, ele is $e")}
                                                  //> index id 0, ele is apple
                                                  //| index id 1, ele is banana
                                                  //| index id 2, ele is orange

val fruits = Vector("apple", "banana", "orange")  //> fruits  : scala.collection.immutable.Vector[String] = Vector(apple, banana, o
                                                  //| range)
for ((elem, count) <- fruits.zip(Stream from 1)) {
	println(s"element $count is $elem")       //> element 1 is apple
                                                  //| element 2 is banana
                                                  //| element 3 is orange
}

//类java

val a = Array(1, 2, 3, 4, 5)                      //> a  : Array[Int] = Array(1, 2, 3, 4, 5)
for (e <- a) yield e * 2                          //> res0: Array[Int] = Array(2, 4, 6, 8, 10)

val helpers = Vector("adam", "kim", "melissa")    //> helpers  : scala.collection.immutable.Vector[String] = Vector(adam, kim, meli
                                                  //| ssa)
val caps = helpers.map(e => e.capitalize)         //> caps  : scala.collection.immutable.Vector[String] = Vector(Adam, Kim, Meliss
                                                  //| a)

val lol = List(List(1,2), List(3,4))              //> lol  : List[List[Int]] = List(List(1, 2), List(3, 4))
val result = lol.flatten                          //> result  : List[Int] = List(1, 2, 3, 4)

val bag = List("1", "2", "three", "4", "one hundred seventy five")
																								//> bag  : List[String] = List(1, 2, three, 4, one hundred seventy five)
def toInt(in: String): Option[Int] = {
	try {
		Some(Integer.parseInt(in.trim))
	} catch {
		case e: Exception => None
	}
}                                         //> toInt: (in: String)Option[Int]
bag.flatMap(toInt).sum                    //> res0: Int = 7
bag.map(toInt).flatten.sum                //> res1: Int = 7

collect, diff, distinct,
drop, dropWhile, filter, filterNot, find, foldLeft, foldRight, head,
headOption, init, intersect, last, lastOption, reduceLeft, reduceRight,
remove, slice, tail, take, takeWhile, union

val x = List(15, 10, 5, 8, 20, 12)        //> x  : List[Int] = List(15, 10, 5, 8, 20, 12)
val y = x.groupBy(_ > 10)                 //> y  : scala.collection.immutable.Map[Boolean,List[Int]] = Map(false -> List(10
																								//| , 5, 8), true -> List(15, 20, 12))

val x = List(15, 10, 5, 8, 20, 12)        //> x  : List[Int] = List(15, 10, 5, 8, 20, 12)
val y = x.partition(_ > 10)               //> y  : (List[Int], List[Int]) = (List(15, 20, 12),List(10, 5, 8))

val x = List(15, 10, 5, 8, 20, 12)        //> x  : List[Int] = List(15, 10, 5, 8, 20, 12)
val y = x.span(_ < 20)                    //> y  : (List[Int], List[Int]) = (List(15, 10, 5, 8),List(20, 12))

val x = List(15, 10, 5, 8, 20, 12)        //> x  : List[Int] = List(15, 10, 5, 8, 20, 12)
val y = x.splitAt(2)                      //> y  : (List[Int], List[Int]) = (List(15, 10),List(5, 8, 20, 12))

val nums = (1 to 5).toArray               //> nums  : Array[Int] = Array(1, 2, 3, 4, 5)
nums.sliding(2).toList                    //> res0: List[Array[Int]] = List(Array(1, 2), Array(2, 3), Array(3, 4), Array(4,
																								//|  5))
nums.sliding(2, 2).toList                 //> res1: List[Array[Int]] = List(Array(1, 2), Array(3, 4), Array(5))
nums.sliding(2, 3).toList                 //> res2: List[Array[Int]] = List(Array(1, 2), Array(4, 5))

val women = List("Kim", "Julia")                  //> women  : List[String] = List(Kim, Julia)
val men = List("Al", "Terry")                     //> men  : List[String] = List(Al, Terry)
val couples = women zip men                       //> couples  : List[(String, String)] = List((Kim,Al), (Julia,Terry))
couples.unzip                                     //> res0: (List[String], List[String]) = (List(Kim, Julia),List(Al, Terry))

	val x = Vector(1, 1, 2, 3, 3, 4)          //> x  : scala.collection.immutable.Vector[Int] = Vector(1, 1, 2, 3, 3, 4)
	val y = x.distinct                        //> y  : scala.collection.immutable.Vector[Int] = Vector(1, 2, 3, 4)

(1 to 100).view                                   //> res0: scala.collection.SeqView[Int,scala.collection.immutable.IndexedSeq[Int]
                                                  //| ] = SeqView(...)

Array.range(1, 5)                         //> res0: Array[Int] = Array(1, 2, 3, 4)
List.range(0, 10)                         //> res1: List[Int] = List(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
Vector.range(0, 10, 2)                    //> res2: scala.collection.immutable.Vector[Int] = Vector(0, 2, 4, 6, 8)

object Margin extends Enumeration {
	type Margin = Value
	val TOP, BOTTOM, LEFT, RIGHT = Value
}

Margin.TOP                                //> res0: worksheet.Margin.Value = TOP

val d = ("Debi", 95)                      //> d  : (String, Int) = (Debi,95)
case class Person(name: String)
val t = (3, "Three", new Person("Al"))    //> t  : (Int, String, worksheet.Person) = (3,Three,Person(Al))
t._1                                      //> res0: Int = 3
t._3                                      //> res1: worksheet.Person = Person(Al)

val (x, y, z) = (3, "Three", new Person("Al"))
																								//> x  : Int = 3
																								//| y  : String = Three
																								//| z  : worksheet.Person = Person(Al)

val (x1, _, _) = t                        //> x1  : Int = 3

val b = "AL" -> "Alabama"                 //> b  : (String, String) = (AL,Alabama)

val a = List(10, 5, 8, 1, 7).sorted       //> a  : List[Int] = List(1, 5, 7, 8, 10)
val b = List("banana", "pear", "apple", "orange").sorted
																								//> b  : List[String] = List(apple, banana, orange, pear)
List(10, 5, 8, 1, 7).sortWith(_ < _)      //> res0: List[Int] = List(1, 5, 7, 8, 10)
class Person(var name: String) extends Ordered[Person] {
	override def toString = name
	def compare(that: Person) = {
		if (this.name == that.name)
			0
		else if (this.name > that.name)
			1
		else
			-1
	}
}

val ty = new Person("Tyler")              //> ty  : worksheet.Person = Tyler
val al = new Person("Al")                 //> al  : worksheet.Person = Al
val paul = new Person("Paul")             //> paul  : worksheet.Person = Paul
val dudes = List(ty, al, paul)            //> dudes  : List[worksheet.Person] = List(Tyler, Al, Paul)

dudes.sorted                              //> res1: List[worksheet.Person] = List(Al, Paul, Tyler)

val a = Array("apple", "banana", "cherry")//> a  : Array[String] = Array(apple, banana, cherry)
a.mkString                                //> res0: String = applebananacherry
a.mkString(" ")                           //> res1: String = apple banana cherry
a.mkString(", ")                          //> res2: String = apple, banana, cherry
a.mkString("[", ", ", "]")                //> res3: String = [apple, banana, cherry]

// 1
scala> val list = 1 :: 2 :: 3 :: Nil
list: List[Int] = List(1, 2, 3)
// 2
scala> val list = List(1, 2, 3)
x: List[Int] = List(1, 2, 3)
// 3a
scala> val x = List(1, 2.0, 33D, 4000L)
x: List[Double] = List(1.0, 2.0, 33.0, 4000.0)
322 | Chapter 11: List, Array, Map, Set (and More)
www.it-ebooks.info
// 3b
scala> val x = List[Number](1, 2.0, 33D, 4000L)
x: List[java.lang.Number] = List(1, 2.0, 33.0, 4000)
// 4
scala> val x = List.range(1, 10)
x: List[Int] = List(1, 2, 3, 4, 5, 6, 7, 8, 9)
scala> val x = List.range(0, 10, 2)
x: List[Int] = List(0, 2, 4, 6, 8)
// 5
scala> val x = List.fill(3)("foo")
x: List[String] = List(foo, foo, foo)
// 6
scala> val x = List.tabulate(5)(n => n * n)
x: List[Int] = List(0, 1, 4, 9, 16)
// 7
scala> val x = collection.mutable.ListBuffer(1, 2, 3).toList
x: List[Int] = List(1, 2, 3)
// 8
scala> "foo".toList
res0: List[Char] = List(f, o, o)

import scala.collection.mutable.ListBuffer
var fruits = new ListBuffer[String]()
// add one element at a time to the ListBuffer
fruits += "Apple"
fruits += "Banana"
fruits += "Orange"

val x = List(2)                                   //> x  : List[Int] = List(2)
val y = 1 +: x                                    //> y  : List[Int] = List(1, 2)
val z = 0 :: y                                    //> z  : List[Int] = List(0, 1, 2)

val originalList = List(5, 1, 4, 3, 2)            //> originalList  : List[Int] = List(5, 1, 4, 3, 2)
//通过filter删除
val newList = originalList.filter(_ > 2)          //> newList  : List[Int] = List(5, 4, 3)

import scala.collection.mutable.ListBuffer
val x = ListBuffer(1, 2, 3, 4, 5, 6, 7, 8, 9)
																								//> x  : scala.collection.mutable.ListBuffer[Int] = ListBuffer(1, 2, 3, 4, 5, 6,
																								//|  7, 8, 9)
//通过值删除
x -= 5                                    //> res0: worksheet.x.type = ListBuffer(1, 2, 3, 4, 6, 7, 8, 9)
x -= (2, 3)                               //> res1: worksheet.x.type = ListBuffer(1, 4, 6, 7, 8, 9)
x --= Seq(1, 2, 3)                        //> res2: worksheet.x.type = ListBuffer(4, 6, 7, 8, 9)
//通过索引删除
x.remove(0)                               //> res3: Int = 4
x.remove(1, 3)

val s = 1#::2#::3#::Stream.empty
val s1 = (1 to 1000000000).toStream //不会爆内存

val a = Array(1,2,3)                              //> a  : Array[Int] = Array(1, 2, 3)

var a1:Array[String]=_
a1 = Array("apple","banana")

val a2 = Array.range(1,10)                        //> a2  : Array[Int] = Array(1, 2, 3, 4, 5, 6, 7, 8, 9)

val a3 = Array.range(0,10,2)                      //> a3  : Array[Int] = Array(0, 2, 4, 6, 8)
val a4 = Array.fill(3)("foo");                    //> a4  : Array[String] = Array(foo, foo, foo)
val a5 = Array.tabulate(5)(n=>n*n)                //> a5  : Array[Int] = Array(0, 1, 4, 9, 16)
val a6 = List(1,2,3).toArray                      //> a6  : Array[Int] = Array(1, 2, 3)
val a7 = "Hello".toArray                          //> a7  : Array[Char] = Array(H, e, l, l, o)

import scala.collection.mutable.ArrayBuffer
var c = ArrayBuffer[String]()                     //> c  : scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer()
c += "aa"                                         //> res0: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer(aa)
c += "bb"                                         //> res1: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer(aa, bb)
c ++=Seq("cc","dd")                               //> res2: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer(aa, bb, cc,
                                                  //|  dd)
c.append("ee","ff")

val rows = 2                                      //> rows  : Int = 2
val cols = 3                                      //> cols  : Int = 3
val a = Array.ofDim[String](rows, cols)           //> a  : Array[Array[String]] = Array(Array(null, null, null), Array(null, null,
                                                  //| null))
a(0)(0) = "a"
a(0)(1) = "b"
a(0)(2) = "c"
a(1)(0) = "d"
a(1)(1) = "e"
a(1)(2) = "f"

a                                                 //> res0: Array[Array[String]] = Array(Array(a, b, c), Array(d, e, f))

val a = Array(Array("a", "b", "c"), Array("d", "e"))
                                                  //> a  : Array[Array[String]] = Array(Array(a, b, c), Array(d, e))

val states = Map("AL" -> "Alabama", "AK" -> "Alaska")
                                                  //> states  : scala.collection.immutable.Map[String,String] = Map(AL -> Alabama,
                                                  //| AK -> Alaska)
var states = collection.mutable.Map[String, String]()
                                                  //> states  : scala.collection.mutable.Map[String,String] = Map()

var states = collection.mutable.Map[String, String]()
																								//> states  : scala.collection.mutable.Map[String,String] = Map()
//添加或修改
states("AK") = "Alaska"
states += ("AL" -> "Alabama")             //> res0: scala.collection.mutable.Map[String,String] = Map(AL -> Alabama, AK ->
																								//|  Alaska)
states += ("AR" -> "Arkansas", "AZ" -> "Arizona")
																								//> res1: scala.collection.mutable.Map[String,String] = Map(AZ -> Arizona, AL ->
																								//|  Alabama, AR -> Arkansas, AK -> Alaska)
states ++= List("CA" -> "California", "CO" -> "Colorado")
																								//> res2: scala.collection.mutable.Map[String,String] = Map(CO -> Colorado, AZ -
																								//| > Arizona, AL -> Alabama, CA -> California, AR -> Arkansas, AK -> Alaska)
//删除
states -= "AR"                            //> res3: scala.collection.mutable.Map[String,String] = Map(CO -> Colorado, AZ -
																								//| > Arizona, AL -> Alabama, CA -> California, AK -> Alaska)

states -= ("AL", "AZ")                    //> res4: scala.collection.mutable.Map[String,String] = Map(CO -> Colorado, CA -
																								//| > California, AK -> Alaska)
states --= List("AL", "AZ")               //> res5: scala.collection.mutable.Map[String,String] = Map(CO -> Colorado, CA -
																								//| > California, AK -> Alaska)
//
states("AK") = "Alaska, A Really Big State"

states.put("CO", "Colorado")              //> res6: Option[String] = Some(Colorado)

states.retain((k,v) => k == "AK")                //> res7: scala.collection.mutable.Map[String,String] = Map(AK -> Alaska, A Real
																								//| ly Big State)
states.remove("AK")                              //> res8: Option[String] = Some(Alaska, A Really Big State)
states.clear

val a = Map("AL" -> "Alabama") //> a  : scala.collection.immutable.Map[String,String] = Map(AL -> Alabama)
//添加或更新
val b = a + ("AK" -> "Alaska") //> b  : scala.collection.immutable.Map[String,String] = Map(AL -> Alabama, AK ->
//|  Alaska)
val c = b + ("AR" -> "Arkansas", "AZ" -> "Arizona")
//> c  : scala.collection.immutable.Map[String,String] = Map(AL -> Alabama, AK -
//| > Alaska, AR -> Arkansas, AZ -> Arizona)

val e = c - "AR" //> e  : scala.collection.immutable.Map[String,String] = Map(AL -> Alabama, AK -
//| > Alaska, AZ -> Arizona)
val f = e - "AZ" - "AL" //> f  : scala.collection.immutable.Map[String,String] = Map(AK -> Alaska)

var x = f; //> x  : scala.collection.immutable.Map[String,String] = Map(AK -> Alaska)
x += ("AC" -> "AC");
println(x) //> Map(AK -> Alaska, AC -> AC)

val states = Map("AL" -> "Alabama", "AK" -> "Alaska", "AZ" -> "Arizona")
																								//> states  : scala.collection.immutable.Map[String,String] = Map(AL -> Alabama,
																								//| AK -> Alaska, AZ -> Arizona)
val s = states.getOrElse("FOO", "No such state")
																								//> s  : String = No such state
val az1 = states.get("AZ")                //> az1  : Option[String] = Some(Arizona)
val az2 = states.get("FOO")               //> az2  : Option[String] = None
val az = states("AZ")                     //> az  : String = Arizona

//不存在会抛异常
val ac = states("AC")                     //> java.util.NoSuchElementException: key not found: AC

val ratings = Map("Lady in the Water"-> 3.0,
 "Snakes on a Plane"-> 4.0,
 "You, Me and Dupree"-> 3.5)                      //> ratings  : scala.collection.immutable.Map[String,Double] = Map(Lady in the W
                                                  //| ater -> 3.0, Snakes on a Plane -> 4.0, You, Me and Dupree -> 3.5)

for ((k,v) <- ratings) println(s"key: $k, value: $v")
                                                  //> key: Lady in the Water, value: 3.0
                                                  //| key: Snakes on a Plane, value: 4.0
                                                  //| key: You, Me and Dupree, value: 3.5

ratings.foreach {
 case(movie, rating) => println(s"key: $movie, value: $rating")
}                                                 //> key: Lady in the Water, value: 3.0
                                                  //| key: Snakes on a Plane, value: 4.0
                                                  //| key: You, Me and Dupree, value: 3.5

ratings.foreach(x => println(s"key: ${x._1}, value: ${x._2}"))
                                                  //> key: Lady in the Water, value: 3.0
                                                  //| key: Snakes on a Plane, value: 4.0
                                                  //| key: You, Me and Dupree, value: 3.5

ratings.keys.foreach((movie) => println(movie))   //> Lady in the Water
                                                  //| Snakes on a Plane
                                                  //| You, Me and Dupree
ratings.keys.foreach(println)                     //> Lady in the Water
                                                  //| Snakes on a Plane
                                                  //| You, Me and Dupree
ratings.values.foreach((rating) => println(rating))
                                                  //> 3.0
                                                  //| 4.0
                                                  //| 3.5

val reverseMap = for ((k,v) <- map) yield (v, k)

val states = Map(
	"AK" -> "Alaska",
	"IL" -> "Illinois",
	"KY" -> "Kentucky")               //> states  : scala.collection.immutable.Map[String,String] = Map(AK -> Alaska,
																								//| IL -> Illinois, KY -> Kentucky)
if (states.contains("FOO")) println("Found foo") else println("No foo")
																								//> No foo

states.valuesIterator.exists(_.contains("ucky"))
																								//> res0: Boolean = true
states.valuesIterator.exists(_.contains("yucky"))
																								//> res1: Boolean = false

var x = collection.mutable.Map(1 -> "a", 2 -> "b", 3 -> "c")
																								//> x  : scala.collection.mutable.Map[Int,String] = Map(2 -> b, 1 -> a, 3 -> c)
x.retain((k, v) => k > 1)                 //> res0: scala.collection.mutable.Map[Int,String] = Map(2 -> b, 3 -> c)
x.transform((k, v) => v.toUpperCase)      //> res1: scala.collection.mutable.Map[Int,String] = Map(2 -> B, 3 -> C)

val y = x.filterKeys(_ > 2)               //> y  : scala.collection.Map[Int,String] = Map(3 -> C)

var m = Map(1 -> "a", 2 -> "b", 3 -> "c") //> m  : scala.collection.immutable.Map[Int,String] = Map(1 -> a, 2 -> b, 3 -> c
																								//| )
m.filter((t) => t._1 > 1)                 //> res2: scala.collection.immutable.Map[Int,String] = Map(2 -> b, 3 -> c)
m.take(2)                                 //> res3: scala.collection.immutable.Map[Int,String] = Map(1 -> a, 2 -> b)

//默认存储无序的无法排序
val grades = Map("Kim" -> 90,
	"Al" -> 85,
	"Melissa" -> 95,
	"Emily" -> 91,
	"Hannah" -> 92)                   //> grades  : scala.collection.immutable.Map[String,Int] = Map(Hannah -> 92, Mel
																								//| issa -> 95, Kim -> 90, Emily -> 91, Al -> 85)

import scala.collection.immutable.ListMap
ListMap(grades.toSeq.sortBy(_._1): _*)    //> res0: scala.collection.immutable.ListMap[String,Int] = Map(Al -> 85, Emily -
																								//| > 91, Hannah -> 92, Kim -> 90, Melissa -> 95)

ListMap(grades.toSeq.sortWith(_._1 < _._1): _*)
																								//> res1: scala.collection.immutable.ListMap[String,Int] = Map(Al -> 85, Emily -
																								//| > 91, Hannah -> 92, Kim -> 90, Melissa -> 95)
ListMap(grades.toSeq.sortWith(_._1 > _._1): _*)
																								//> res2: scala.collection.immutable.ListMap[String,Int] = Map(Melissa -> 95, Ki
																								//| m -> 90, Hannah -> 92, Emily -> 91, Al -> 85)
ListMap(grades.toSeq.sortBy(_._2): _*)    //> res3: scala.collection.immutable.ListMap[String,Int] = Map(Al -> 85, Kim ->
																								//| 90, Emily -> 91, Hannah -> 92, Melissa -> 95)
ListMap(grades.toSeq.sortWith(_._2 < _._2): _*)
																								//> res4: scala.collection.immutable.ListMap[String,Int] = Map(Al -> 85, Kim ->
																								//| 90, Emily -> 91, Hannah -> 92, Melissa -> 95)
ListMap(grades.toSeq.sortWith(_._2 > _._2): _*)
																								//> res5: scala.collection.immutable.ListMap[String,Int] = Map(Melissa -> 95, Ha
																								//| nnah -> 92, Emily -> 91, Kim -> 90, Al -> 85)

//TODO 看书_*

val grades = Map("Al" -> 80, "Kim" -> 95, "Teri" -> 85, "Julia" -> 90)
																								//> grades  : scala.collection.immutable.Map[String,Int] = Map(Al -> 80, Kim -> 9
																								//| 5, Teri -> 85, Julia -> 90)
grades.keysIterator.max                   //> res0: String = Teri
grades.max                                //> res1: (String, Int) = (Teri,85)

grades.valuesIterator.max                 //> res2: Int = 95
grades.keysIterator.reduceLeft((x, y) => if (x.length > y.length) x else y)
																								//> res3: String = Julia

import scala.io.Source
val fileName = "d:/test.txt"              //> fileName  : String = d:/test.txt

val buffer = Source.fromFile(fileName)    //> buffer  : scala.io.BufferedSource = non-empty iterator

for(line<-buffer.getLines()){
	println(line)                     //> Line1
																								//| Line2
}

buffer.mkString                           //> res0: String = ""


//getLine返回一个迭代器

def using[A<:{def close():Unit}, B](resource: A)(f:A=>B):B = {
	try{
		f(resource)
	} finally {
		resource.close()
	}
}                                         //> using: [A <: AnyRef{def close(): Unit}, B](resource: A)(f: A => B)B

val fileName = "d:/test.txt"              //> fileName  : String = d:/test.txt
val buffer = Source.fromFile(fileName)    //> buffer  : scala.io.BufferedSource = non-empty iterator

using(buffer)(_.mkString);                //> res0: String = "Line1
																								//| Line2
																								//| "

// 将上定义 def using[A<:{def close():Unit}, B](resource: A)(f:A=>B):B

def readTextFile(fileName:String):Option[List[String]] = {
	try{
		val lines = using(io.Source.fromFile(fileName))( source => {
			(for(line <- source.getLines()) yield line).toList
		})
		Some(lines)
	} catch {
		case e: Exception => None
	}
}                                         //> readTextFile: (fileName: String)Option[List[String]]


val fileName = "d:/test.txt"              //> fileName  : String = d:/test.txt

readTextFile(fileName)                    //> res0: Option[List[String]] = Some(List(Line1, Line2))

import scala.io.Source
val fileName = "d:/test.txt"              //> fileName  : String = d:/test.txt
val buffer = Source.fromString("""Line1
Line2
""")                                              //> buffer  : scala.io.Source = non-empty iterator


for (line <- buffer.getLines()) {
	println(line)                     //> Line1
																								//| Line2
}

import java.io._
// 创建一个类
@SerialVersionUID(123L)
class Stock(var symbol: String, var price: BigDecimal)
	extends Serializable {
	override def toString = f"$symbol%s is ${price.toDouble}%.2f"
}


// (1) 创建一个实例
val nflx = new Stock("NFLX", BigDecimal(85.00))
// (2) 创建文件流，将对象序列化后写入文件
val oos = new ObjectOutputStream(new FileOutputStream("/tmp/nflx"))
oos.writeObject(nflx)
oos.close
// (3) 从文件中读取对象并实例化
val ois = new ObjectInputStream(new FileInputStream("/tmp/nflx"))
val stock = ois.readObject.asInstanceOf[Stock]
ois.close
// (4) 测试对象
println(stock)

scala> "pwd".!
/c/Users/xxxx
res0: Int = 0

scala> val code = "pwd".!
/c/Users/xxxx
code: Int = 0

scala> code
res2: Int = 0

scala> Process("pwd").!
/c/Users/xxxx
res3: Int = 0

scala> Seq("pwd").!
/c/Users/xxxx
res4: Int = 0

val p = Process("pwd").lines

scala> val result = "ipconfig".!!
result: String =
"
Windows IP 配置


无线局域网适配器 WLAN:

   媒体状态  . . . . . . . . . . . . : 媒体已断开连接
   连接特定的 DNS 后缀 . . . . . . . : workgroup

无线局域网适配器 本地连接* 2:

   媒体状态  . . . . . . . . . . . . : 媒体已断开连接
   连接特定的 DNS 后缀 . . . . . . . :

以太网适配器 以太网:

   连接特定的 DNS 后缀 . . . . . . . :
   本地链接 IPv6 地址. . . . . . . . : fe80::24c3:eb4a:ec45:2b2e%18
   IPv4 地址 . . . . . . . . . . . . : 172.19.208.233
   子网掩码  . . . . . . . . . . . . : 255.255.240.0
   默认网关. . . . . . . . . . . . . : 172.19.208.1

隧道适配器 本地连接* 11:

   连接特定的 DNS 后缀 . . . . . . . :
   IPv6 地址 . . . . . . . . . . . . : 2001:0:5ef5:79fd:3c7d:1a4d:53ec:2f16
   本地链接 IPv6 地址. . . . . . . . : fe80::3c7d:1a4d:53ec:2f16%17
   默认网关. . . . . . . . . . . . . : ::

隧道适配器 isatap.{F8C49FBC-3672-45C1-86F5-68A03FD0F370}:
...

import akka.actor.Actor
import akka.actor.ActorSystem
import akka.actor.Props
class HelloActor extends Actor {
	def receive = {
		case "hello" => println("hello back at you")
		case _ => println("huh?")
	}
}

object Main extends App {
	// 初始化一个actor系统，并命名
	val system = ActorSystem("HelloSystem")
	// 创建并开启一个actor，名字叫helloactor，是HelloActor的一个实例
	val helloActor = system.actorOf(Props[HelloActor], name = "helloactor")
	// 给actor发送两个消息
	helloActor ! "hello"
	helloActor ! "buenos dias"
	// 关闭actor系统
	system.shutdown
}

/*输出
hello back at you
huh?
*/

import akka.actor._
case object PingMessage //来自ping的消息
case object PongMessage //来自Pong的消息
case object StartMessage //开始启动的消息
case object StopMessage //停止的消息


class Ping(pong: ActorRef) extends Actor {
	var count = 0 //计数器
	def incrementAndPrint { count += 1; println("ping") }
	def receive = { //回复消息
		case StartMessage => //接收到开始消息
			incrementAndPrint //计数器++，
			pong ! PingMessage //给pong发送消息
		case PongMessage =>
			incrementAndPrint
			if (count > 99) {
				sender ! StopMessage
				println("ping stopped")
				context.stop(self)
			} else {
				sender ! PingMessage
			}
		case _ => println("Ping got something unexpected.")
	}
}
class Pong extends Actor {
	def receive = {
		case PingMessage =>
			println(" pong")
			sender ! PongMessage
		case StopMessage =>
			println("pong stopped")
			context.stop(self)
		case _ => println("Pong got something unexpected.")
	}
}
object Main extends App {
	val system = ActorSystem("PingPongSystem")
	val pong = system.actorOf(Props[Pong], name = "pong")
	val ping = system.actorOf(Props(new Ping(pong)), name = "ping")
	// start the action
	ping ! StartMessage
	// commented-out so you can see all the output
	Thread.sleep(1000);
	system.shutdown
}
/*输出
ping
 pong
......
ping stopped
pong stopped
*/

import akka.actor._
class Kenny extends Actor {
	println("进入 Kenny 构造函数")
	override def preStart { println("kenny: preStart方法执行") }
	override def postStop { println("kenny: postStop方法执行") }
	override def preRestart(reason: Throwable, message: Option[Any]) {
		println("kenny: preRestart方法执行")
		println(s" 消息内容: ${message.getOrElse("")}")
		println(s" 原因: ${reason.getMessage}")
		super.preRestart(reason, message)
	}
	override def postRestart(reason: Throwable) {
		println("kenny: postRestart方法执行")
		println(s" 原因: ${reason.getMessage}")
		super.postRestart(reason)
	}
	def receive = {
		case ForceRestart => throw new Exception("Boom!")
		case _ => println("Kenny 收到一个消息")
	}
}
case object ForceRestart

object Main extends App {
	val system = ActorSystem("LifecycleDemo")
	val kenny = system.actorOf(Props[Kenny], name = "Kenny")
	println("发送 kenny 一个简单的字符串消息")
	kenny ! "hello"
	Thread.sleep(1000)
	println("让 kenny 重启")
	kenny ! ForceRestart
	Thread.sleep(1000)
	println("停止 kenny")
	system.stop(kenny)
	println("关闭系统")
	system.shutdown
}
/*输出
发送 kenny 一个简单的字符串消息
进入 Kenny 构造函数
kenny: preStart方法执行
Kenny 收到一个消息
让 kenny 重启
kenny: preRestart方法执行
 消息内容: ForceRestart
 原因: Boom!
kenny: postStop方法执行
进入 Kenny 构造函数
kenny: postRestart方法执行
 原因: Boom!
kenny: preStart方法执行
[ERROR] [12/05/2016 23:22:35.325] [LifecycleDemo-akka.actor.default-dispatcher-7] [akka://LifecycleDemo/user/Kenny] Boom!
java.lang.Exception: Boom!
	at Kenny$$anonfun$receive$1.applyOrElse(Main.scala:18)
	at akka.actor.Actor$class.aroundReceive(Actor.scala:484)
	at Kenny.aroundReceive(Main.scala:2)
	at akka.actor.ActorCell.receiveMessage(ActorCell.scala:526)
	at akka.actor.ActorCell.invoke(ActorCell.scala:495)
	at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:257)
	at akka.dispatch.Mailbox.run(Mailbox.scala:224)
	at akka.dispatch.Mailbox.exec(Mailbox.scala:234)
	at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
	at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
	at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
	at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)

停止 kenny
关闭系统
kenny: postStop方法执行
*/

val system = ActorSystem("HelloSystem")
// 系统创建
val helloActor = system.actorOf(Props[HelloActor], name = "helloactor"

class Parent extends Actor {
 val child = context.actorOf(Props[Child], name = "Child")
 // more code here ...
}

import akka.actor._

class TestActor extends Actor {
	def receive = {
		case _ => println("收到一个消息")
	}
}
object Main extends App {
	val actorSystem = ActorSystem("SystemStopExample")
	val actor = actorSystem.actorOf(Props[TestActor], name = "test")
	actor ! "hello"
	// 停止
	actorSystem.stop(actor)
	actor ! "hello"
	actorSystem.shutdown
}
//有两种可能输出
/*
1、
收到一个消息
收到一个消息
2、
收到一个消息
[INFO] [12/06/2016 22:41:44.804] [SystemStopExample-akka.actor.default-dispatcher-7] [akka://SystemStopExample/user/test] Message [java.lang.String] from Actor[akka://SystemStopExample/deadLetters] to Actor[akka://SystemStopExample/user/test#500643557] was not delivered. [1] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
*/

import akka.actor._
class TestActor extends Actor {
	def receive = {
		case s: String => println("收到的消息: " + s)
		case _ => println("TestActor 收到一个位置消息")
	}
	override def postStop { println("TestActor::postStop 方法执行") }
}
object Main extends App {
	val system = ActorSystem("PoisonPillTest")
	val actor = system.actorOf(Props[TestActor], name = "test")
	// a simple message
	actor ! "在 PoisonPill消息之前"
	// the PoisonPill
	actor ! PoisonPill
	// these messages will not be processed
	actor ! "在 PoisonPill消息之前"
	actor ! "hello?!"
	system.shutdown
}

/*
收到的消息: 在 PoisonPill消息之前
TestActor::postStop 方法执行
[INFO] [12/06/2016 22:44:47.361] [PoisonPillTest-akka.actor.default-dispatcher-4] [akka://PoisonPillTest/user/test] Message [java.lang.String] from Actor[akka://PoisonPillTest/deadLetters] to Actor[akka://PoisonPillTest/user/test#-390700988] was not delivered. [1] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
[INFO] [12/06/2016 22:44:47.361] [PoisonPillTest-akka.actor.default-dispatcher-4] [akka://PoisonPillTest/user/test] Message [java.lang.String] from Actor[akka://PoisonPillTest/deadLetters] to Actor[akka://PoisonPillTest/user/test#-390700988] was not delivered. [2] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
*/

import akka.actor._
import akka.pattern.gracefulStop
import scala.concurrent.{ Await, ExecutionContext, Future }
import scala.concurrent.duration._
import scala.language.postfixOps
class TestActor extends Actor {
	def receive = {
		case _ => println("TestActor 收到消息")
	}
	override def postStop { println("TestActor: postStop方法执行") }
}

object Main extends App {
	val system = ActorSystem("GracefulStopTest")
	val testActor = system.actorOf(Props[TestActor], name = "TestActor")
	// try to stop the actor gracefully
	try {
		val stopped: Future[Boolean] = gracefulStop(testActor, 2 seconds, "stop")
		//Await.result(stopped, 3 seconds)
		for(i ← 1 to 10) testActor ! "xx"
		println("testActor 被停止")
	} catch {
		case e: Exception => e.printStackTrace
	} finally {
		system.shutdown
	}
}

/*
//Await.result(stopped, 3 seconds)
for(i <- 1 to 10) testActor ! "xx"
这样不会报异常
打开注释将会报异常
*/

//system.shutdown ，已废弃
system.terminate //关闭

class Kenny extends Actor {
	def receive = {
		case _ => println("Kenny 收到一个消息")
	}
}
class Parent extends Actor {
	// start Kenny as a child, then keep an eye on it
	val kenny = context.actorOf(Props[Kenny], name = "Kenny")
	context.watch(kenny)
	def receive = {
		case Terminated(kenny) => println("OMG, Kenny被killed")
		case _ => println("Parent 收到一个消息")
	}
}

object Main extends App {
	val system = ActorSystem("DeathWatchTest")
	val parent = system.actorOf(Props[Parent], name = "Parent")
	// 获取kenny的引用
	val kenny = system.actorSelection("/user/Parent/Kenny")
	kenny ! PoisonPill
	Thread.sleep(5000)
	println("calling system.shutdown")
	system.terminate
}

val kenny = system.actorSelection("/user/Parent/Kenny")
val kenny = context.actorSelection("../Kenny")
val kenny = system.actorFor("akka://DeathWatchTest/user/Parent/Kenny")
val kenny = system.actorFor(Seq("user", "Parent", "Kenny"))
val kenny = system.actorFor(Seq("..", "Kenny"))

import scala.concurrent.{ Await, Future }
import scala.concurrent.duration._
import scala.concurrent.ExecutionContext.Implicits.global

object Main extends App {
	def sleep(time: Long) { Thread.sleep(time) }

	// 使用 'time' 方法
	implicit val baseTime = System.currentTimeMillis
	// 2 - 创建一个 Future，相当于创建了一个新线程，主线程不会阻塞，且是call-by-name
	val f = Future {
		sleep(500)
		1 + 1
	}
	// 3 - 这会阻塞，获得结果
	val result = Await.result(f, 1 second)
	println(result)
	sleep(1000)
}

import scala.concurrent.{ Future }
import scala.concurrent.ExecutionContext.Implicits.global
import scala.util.{ Failure, Success }
import scala.util.Random
object Main extends App {

	def sleep(time: Long) { Thread.sleep(time) }

	println("开启一个计算")
	val f = Future {
		sleep(Random.nextInt(500))
		42
	}
	println("onComplete方法前")
	f.onComplete {
		case Success(value) => println(s"转到了回调，参数为 = $value")
		case Failure(e) => e.printStackTrace
	}
	// 做你剩下的工作
	println("A ..."); sleep(100)
	println("B ..."); sleep(100)
	println("C ..."); sleep(100)
	println("D ..."); sleep(100)
	println("E ..."); sleep(100)
	println("F ..."); sleep(100)
	sleep(2000)
}
/*输出为：
开启一个计算
onComplete方法前
A ...
B ...
C ...
D ...
转到了回调，参数为 = 42
E ...
F ...
*/

//同上......
	f.onComplete {
		case Success(value) => println(s"转到了回调，参数为 = $value")
		case Failure(e) => e.printStackTrace
	}

	f onSuccess {
		case result => println(s"成功的回调: $result")
	}
	f onFailure {
		case t => println(s"失败回调: ${t.getMessage}")
	}
//同上......
/*输出
开启一个计算
onComplete方法前
A ...
B ...
成功的回调: 42
转到了回调，参数为 = 42
C ...
D ...
E ...
F ...
*/

import scala.concurrent.{ Await, Future, future }
import scala.concurrent.ExecutionContext.Implicits.global
import scala.util.{ Failure, Success }
object Main extends App {
	def sleep(time: Long) { Thread.sleep(time) }
	implicit val baseTime = System.currentTimeMillis

	def longRunningComputation(i: Int): Future[Int] = future {
		sleep(100)
		i + 1
	}
	// 不阻塞
	longRunningComputation(11).onComplete {
		case Success(result) => println(s"result = $result")
		case Failure(e) => e.printStackTrace
	}
	// keep the jvm from shutting down
	sleep(1000)
}
/*输出：
result = 12
*/

import scala.concurrent.{ Future, future }
import scala.concurrent.ExecutionContext.Implicits.global
import scala.util.{ Failure, Success }
import scala.util.Random

object Cloud {
	def sleep(time: Long) { Thread.sleep(time) }
	def runAlgorithm(i: Int): Future[Int] = future {
		sleep(Random.nextInt(500))
		val result = i + 10
		println(s"从“云中”返回结果: $result")
		result
	}
}

object Main extends App {

	def sleep(time: Long) { Thread.sleep(time) }
	println("开始一组future")
	val result1 = Cloud.runAlgorithm(10)
	val result2 = Cloud.runAlgorithm(20)
	val result3 = Cloud.runAlgorithm(30)
	println("在 for-comprehension之前")
	val result = for {
		r1 <- result1
		r2 <- result2
		r3 <- result3
	} yield (r1 + r2 + r3) //将三个任务完成后的结果的操作
	println("在 onSuccess回调函数之前")
	result onSuccess {
		case result => println(s"total = $result")
	}
	println("在最后睡眠之前")
	sleep(2000) // keep the jvm alive
}
/*输出：
开始一组future
在 for-comprehension之前
在 onSuccess回调函数之前
在最后睡眠之前
从“云中”返回结果: 20
从“云中”返回结果: 30
从“云中”返回结果: 40
total = 90
*/

import akka.actor._
import akka.pattern.ask
import akka.util.Timeout
import scala.concurrent.{ Await, ExecutionContext, Future }
import scala.concurrent.duration._
import scala.language.postfixOps

case object AskNameMessage

class TestActor extends Actor {
	def receive = {
		case AskNameMessage => // respond to the 'ask' request
			sender ! "Fred"
		case _ => println("that was unexpected")
	}
}

object Main extends App {
	// 创建系统
	val system = ActorSystem("AskTestSystem")
	val myActor = system.actorOf(Props[TestActor], name = "myActor")
	// (1) 询问actor方式1
	implicit val timeout = Timeout(5 seconds)
	val future = myActor ? AskNameMessage
	val result = Await.result(future, timeout.duration).asInstanceOf[String]
	println(result)
	// (2) 另一种方法
	val future2: Future[String] = ask(myActor, AskNameMessage).mapTo[String]
	val result2 = Await.result(future2, 1 second)
	println(result2)
	system.shutdown
}
/*输出：
Fred
Fred
*/

import akka.actor._
case object ActNormalMessage
case object TryToFindSolution
case object BadGuysMakeMeAngry
class DavidBanner extends Actor {
	import context._
	def angryState: Receive = {
		case ActNormalMessage =>
			println("Phew, I'm back to being David.")
			become(normalState)
	}
	def normalState: Receive = {
		case TryToFindSolution =>
			println("Looking for solution to my problem ...")
		case BadGuysMakeMeAngry =>
			println("I'm getting angry...")
			become(angryState)
	}
	def receive = {
		case BadGuysMakeMeAngry => become(angryState)
		case ActNormalMessage => become(normalState)
	}
}
object Main extends App {
	val system = ActorSystem("BecomeHulkExample")
	val davidBanner = system.actorOf(Props[DavidBanner], name = "DavidBanner")
	davidBanner ! ActNormalMessage // init to normalState
	davidBanner ! TryToFindSolution
	davidBanner ! BadGuysMakeMeAngry
	Thread.sleep(1000)
	davidBanner ! ActNormalMessage
	system.shutdown
}
/*输出：
Looking for solution to my problem ...
I'm getting angry...
Phew, I'm back to being David.
*/

scala> val v = Vector.range(0, 10)
v: scala.collection.immutable.Vector[Int] = Vector(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)

scala> v.foreach(print)
0123456789

scala> v.par.foreach(print)
5678901234
scala> v.par.foreach(print)
0123456789

scala> v.par.foreach{ e => print(e); Thread.sleep(50) }
0516273894