update scala sprint2

src/docs/sprint.md

@@ -186,7 +186,7 @@ mulBy(3)(4)
 >类型构造器原理和函数相似，只不过类型构造器处理的是类型，在函数中，我传入一个a,返回一个b,在类型构造器中，我传入一个类型，返回一个类型
 ```scala
 List[_]
-List[String]
+type listStting = List[String]
 List[Int]
 Map[_,_]
 Map[String,Int]
@@ -232,6 +232,13 @@ Pure.println("Rhyme")
 ```scala
 val a = ("Rhyme", 20)
 val (first, second) = a
+
+obj match {
+    if(obj is not null && obj.isA) => (A)obj.id
+    case A(id) => id 
+    case B(name) => 
+    case C(sex) => 
+}
 ```
 
 

src/main/scala/Chapter14.md

@@ -0,0 +1,98 @@
+## 14.1更好的Switch
+
+1.模式匹配不会发生case穿透
+
+2.模式匹配可以是任意的类型
+
+3.使用|来分隔多个选项
+
+```scala
+var sign = ""
+var ch: Char = 'A'
+sign = ch match {
+  case 'A' => "A"
+  case 'B' => "B"
+  case _ => "Others"
+}
+```
+
+## 14.2 守卫
+
+> 有了守卫，就可以处理一些通用的情况，例如case 1,case 2 ,case 3，...case 10就可以直接用if(ch <10)表示
+
+```scala
+ch match {
+  case _ if Character.isDigit(ch) => digit = Character.digit(ch, 10)
+}
+```
+
+## 14.3 模式中的变量
+
+> 可以在模式匹配中将变量赋值给变量
+
+```scala
+var digit = 1
+ch = '2'
+ch match {
+  case _ if Character.isDigit(ch) => digit = Character.digit(ch, 10)
+}
+digit
+```
+
+## 14.4类型模式 
+
+> 代替isIntanceOf操作，更加推荐使用模式匹配来进行类型的判断与转化
+
+```scala
+def typeMatch[A](x: A) = {
+  x match {
+    case x: Int => x
+    case s: String => Integer.parseInt(s)
+    case _: BigInt => Int.MaxValue
+    case _ => 0
+  }
+}
+
+typeMatch("234")
+```
+
+> 匹配类型的时候必须给出变量名，否则将拿对象本身来进行匹配
+
+> 模式匹配发生在运行期，Java虚拟机中泛型的信息会被擦除，所以以下匹配特定类型的Map是错误的
+
+```scala
+obj match {
+  case m: Map[Int, String]=> ...
+}
+```
+
+## 14.5 匹配数组、列表、元组
+
+数组、列表、元组（析构匹配）
+
+```scala
+val a1 = Array(0, 1, 2, 3)
+val a2 = Array(5, 6, 7, 8)
+a1 match {
+  case Array(0) => "0"
+  case Array(x, y) => s"$x $y"
+  //  case Array(0, _*) => "0..."
+  case Array(0, rest@_*) => rest.max
+  case _ => "something else"
+}
+```
+
+> 模式中使用的变量名都用小写，大写的变量名会被当做常量来看待
+
+> 如果模式中有不同的分支，除了下划线，别的都不能用
+
+```scala
+var t = (1, 2)
+t match {
+  case (0, _) | (_, 0) => "0 _ _ 0"
+  case (0, x) | (x, 0) => "错误"// 不能这么用
+}
+```
+
+
+

src/main/scala/Test.scala

@@ -3,6 +3,6 @@ object Test {
     println("pppp")
 
     val list = Seq(1,4,3,6)
-    list.sortWith()
+//    list.sortWith()
   }
 }

src/main/scala/Tree2.scala

@@ -0,0 +1,32 @@
+/**
+  * Created by dripower on 2018/7/18.
+  */
+trait Tree2[+A] {
+  def scanLeft[R](init: R)(f: (R, A) => R): R ={
+    this match {
+      case TNil2 => init
+      case Node2(data,left,right) => left.scanLeft(f(init, data))(f);right.scanLeft(f(init, data))(f)
+      case Node2(data,left,_) => left.scanLeft(f(init, data))(f)
+      case Node2(data,_,right) => right.scanLeft(f(init, data))(f)
+    }
+  }
+  //  def printDot(): String ={
+  //
+  //  }
+  //  def reverse: Tree2[A] ={
+  //    this match {
+  //      case TNil2 => return null
+  //      case _ =>
+  //    }
+  //  }
+}
+case class Node2[A](data: A, left: Tree2[A], right: Tree2[A]) extends Tree2[A]
+case object TNil2 extends Tree2[Nothing]
+
+object testTree2 {
+  def main(args: Array[String]): Unit = {
+    val Tree2: Node2[Int] = Node2(1,Node2(2,TNil2,TNil2),Node2(3,TNil2,TNil2))
+    val fun = (init: Int,value: Int) => init + value
+    println(Tree2.scanLeft(0)(fun))
+  }
+}

src/main/scala/chapter14/Chapter14.sc

@@ -0,0 +1,53 @@
+var sign = ""
+var ch: Char = 'A'
+sign = ch match {
+  case 'A' => "A"
+  case 'B' => "B"
+  case _ => "Others"
+}
+
+//守卫
+var digit = 1
+ch = '2'
+ch match {
+  case _ if Character.isDigit(ch) => digit = Character.digit(ch, 10)
+}
+digit
+
+//类型模式
+var i = 2
+i match {
+  case s: Int => s
+}
+
+def typeMatch[A](x: A) = {
+  x match {
+    case x: Int => x
+    case s: String => Integer.parseInt(s)
+    case BigInt => -1
+    case _: BigInt => Int.MaxValue
+    case _ => 0
+  }
+}
+
+var b: BigInt = BigInt(234)
+
+typeMatch(b)
+
+val a1 = Array(0, 1, 2, 3)
+val a2 = Array(5, 6, 7, 8)
+a1 match {
+  case Array(0) => "0"
+  case Array(x, y) => s"$x $y"
+  //  case Array(0, _*) => "0..."
+  case Array(0, rest@_*) => rest.max
+  case _ => "something else"
+}
+
+val list = List(1, 2, 3, 4)
+
+var t = (1, 2)
+t match {
+  case (0, _) | (_, 0) => "0 _ _ 0"
+  case (0, x) | (x, 0) => "错误"
+}

src/main/scala/chapter2/C2.sc

@@ -0,0 +1,68 @@
+import scala.io.StdIn
+import scala.util.Try
+
+val name = "Rhyme"
+val age = 3
+println(f" Hello $name ,I'm ${age + 3} years old")
+
+//scala.io.StdIn.readLine("your name")
+//scala.io.StdIn.readInt()
+//scala.io.StdIn.readDouble()
+
+val n = 10
+for (n <- 0 to 10) {
+  print(n)
+}
+
+for (i <- 0 to 10; j <- 0 to i if i != j) {
+  print(i * j)
+}
+
+for (i <- 0 to 10; from = 4 - i; j <- from to 3) {
+  print(i * j)
+}
+
+for (i <- 0 to 10; j <- "Rhyme") yield i * j
+
+for {
+  i <- 0 to 10
+  from = 4 - i
+  j <- from to 4
+} yield i * j
+
+// 默认参数
+def decorate(value: String, left: String = "<<", right: String = ">>") = {
+  left + value + right
+}
+
+decorate("Rhyme")
+
+decorate(value = "Rhyme", left = "{", right = "}")
+
+def sum(args: Int*): Int = {
+  var sum = 0
+  for (arg <- args) {
+    sum = sum + arg
+  }
+  sum
+}
+
+sum(1, 2, 3, 4)
+
+def recursiveSum(args: Int*): Int = {
+  if (args.isEmpty) 0 else {
+    args.head + recursiveSum(args.tail: _*)
+  }
+}
+
+recursiveSum(1, 2, 3, 4)
+
+def process(): Unit = {
+  print("Hello")
+}
+
+for (a <- Try {
+  StdIn.readInt()
+}; b <- Try {
+  StdIn.readInt()
+}) yield a / b

src/main/scala/course/Node.scala

@@ -0,0 +1,3 @@
+package course
+
+case class Node[T](ele: T, left: Tree[T], right: Tree[T]) extends Tree[T]

src/main/scala/course/TNil.scala

@@ -0,0 +1,3 @@
+package course
+
+case object TNil extends Tree[Nothing]

src/main/scala/course/TestTree.scala

@@ -0,0 +1,16 @@
+package course
+
+object TestTree {
+  def main(args: Array[String]): Unit = {
+    val leftNode = Node(2, TNil, TNil)
+    val rightNode = Node(3, TNil, TNil)
+    val tree = Node(1, leftNode, rightNode)
+    val fun = (init: Long, value: Int) => init + value
+    println(tree.scanLeft(0L)(fun))
+    print("-----printDot-----")
+    println(tree.printDot())
+    print("-----reverse-----")
+    val reverse = tree.reverse()
+    println(reverse)
+  }
+}

src/main/scala/course/Tree.scala

@@ -0,0 +1,40 @@
+package course
+
+import java.io.PrintWriter
+
+trait Tree[+T] {
+  def scanLeft[R](init: R)(f: (R, T) => R): R = {
+    this match {
+      // 空树的情况
+      case TNil => init
+      // 树非空
+      case Node(value, left, right) =>
+        val leftRes = left.scanLeft(f(init, value))(f)
+        right.scanLeft(leftRes)(f)
+    }
+  }
+
+  def printDot(): String = {
+    val out = new PrintWriter("tree.dot")
+    this match {
+      case TNil => out.write("TNil\n"); "TNil\n"
+      case Node(value, left, right) =>
+        val leftRes = left.printDot()
+        val rightRes = right.printDot()
+        out.write(value.toString + "\n" + leftRes.toString + rightRes.toString)
+        out.flush()
+        out.close()
+        value.toString + "\n" + leftRes.toString + rightRes.toString
+    }
+  }
+
+  def reverse(): Tree[T] = {
+    this match {
+      case TNil => TNil
+      case Node(value, left, right) =>
+        left.reverse()
+        right.reverse()
+        Node(value, right, left)
+    }
+  }
+}

src/test/scala/com/rhyme/TreeTest.scala

@@ -0,0 +1,14 @@
+package com.rhyme
+
+import org.scalatest.{FlatSpec, Matchers}
+import course.Node
+import course.TNil
+
+class TreeTest extends FlatSpec with Matchers {
+  "a course.Tree" should "be same after reverse and reverse" in {
+    val leftNode = Node(2, TNil, TNil)
+    val rightNode = Node(3, TNil, TNil)
+    val tree = Node(1, leftNode, rightNode)
+    tree.reverse().reverse() should be(tree)
+  }
+}