package yjmyzz

import java.io.PrintWriter

import java.util.Date

import scala.io.Source

object ScalaApp02 {

  def main(args: Array[String]) {

    tupleDemo

    println

    mapDemo

    println

    arrayDemo

    println

    fileWriteAndRead

    println(getUrlContent("http://www.cnblogs.com/yjmyzz/"))

  }

  /**

   * 元组示例

   */

  def tupleDemo = {

    //val表示常量（相当于JAVA中的final），var表示变量

    val tuple = ("jimmy", 100, new Date()) //这写法比c#里的Tuple<T>还简洁

    //打印第1，2，3个元素，注意元组下标是从1开始的

    println(tuple._1)

    println(tuple._2)

    println(tuple._3)

  }

  /**

   * 数组示例

   */

  def arrayDemo = {

    var myArr = Array(5, 4, 3, 2, 1) //注意：这里不需要new关键字

    for (i <- myArr) println(i)

    println

    //找出myArr中的偶数

    var even = myArr.filter(i => i % 2 == 0) //这语法的简洁性，快赶上C#的LINQ了

    for (i <- even) println(i)

    println

    scala.util.Sorting.quickSort(even) //排序

    for (i <- even) println(i)

  }

  //Map示例

  def mapDemo = {

    var myMap = Map(("jimmy", 1), ("Mike", 2), ("John", 3));

    //遍历

    for ((k, v) <- myMap) {

      println("key:" + k + "\t,value=" + v);

    }

    println

    println("all keys => ")

    //遍历key

    for (k <- myMap.keys) {

      println(k)

    }

    println

    //遍历value

    println("all values => ")

    for (v <- myMap.values) {

      println(v)

    }

    println

    //遍历key和value，还有一种写法（利用占位符号"_"）

    println("all keys => ")

    for ((k, _) <- myMap) println(k)

    println

    println("all values => ")

    for ((_, v) <- myMap) println(v)

  }

  /**

   * 文件读写示例

   */

  def fileWriteAndRead = {

    val fileName = "scalaTest.txt"

    //写文件

    var writer = new PrintWriter(fileName)

    writer.write("hello scala\n")

    writer.write("hello spark")

    writer.close()

    //读文件

    var fileContent = Source.fromFile(fileName);

    println(fileContent.mkString)

  }

  /**

   * 获取网页内容

   * @param url

   * @return

   */

  def getUrlContent(url: String): String = {

    Source.fromURL(url).mkString

  }

}