大数据系列修炼-Scala课程06

    //定义的正则表达式
    val regex="""([0-9]+) ([a-z]+)""".r //由数字与字母组成的常量
    val numPattern = "[0-9]+".r //由数字组成的常量
    val numberPattern = """\s+[0-9]+\s+""".r //由s与数字+s组成的正则表达式
    println(regex);
    // findAllIn方法返回遍历所有匹配项的迭代器
    for (matchString <- numPattern.findAllIn("99345 Scala, 22298 Spark")) println(matchString)
    // 找到首个匹配项
    println(numberPattern.findFirstIn("99ss java, 222 hadoop"))

 //正则表达式与模式匹配结合
    val numitemPattern="""([0-9]+) ([a-z]+)""".r //正则表达式
    val numitemPattern(num, item) = "99 hadoop" //规定模式
    val line = "93459 spark"
    line match{
      case numitemPattern(num, blog) => println(num + "\t" + blog)
      case _ => println("Oops...")
    }

  //本地函数 就是函数中包含函数 这样就可以使里面的函数使用外面函数的参数
def processData(filename: String, width: Int) {
    def processLine(line: String) {
      if (line.length > width)
        println(filename +": "+ line)
    }
    val source = Source.fromFile(filename)
    for (line <- source.getLines)
      processLine(line)
  }
}

  //一等公民函数
   def main(args: Array[String]): Unit = {
     //启动项中设置的参数
    val width = args(0).toInt
    for (arg <- args.drop(1))
      processData(arg, width)
      var increase = (x: Int) => x + 1
      println(increase(10))
      increase = (x: Int) => x + 9999
      val someNumbers = List(-11, -10, -5, 0, 5, 10)
      //遍历数组
      someNumbers.foreach((x: Int) => print (x))
      println
      //过滤大于0
      someNumbers.filter((x: Int) => x > 0).foreach((x: Int) => print (x))
       println
       //过滤大于0
      someNumbers.filter((x) => x > 0).foreach((x: Int) => print (x))
       println
       //过滤大于0
      someNumbers.filter(x => x > 0).foreach((x: Int) => print (x))
       println
       //过滤大于0
      someNumbers.filter(_ > 0).foreach((x: Int) => print (x))
       println
       //定义两个数字相加
      val f = (_: Int) + (_: Int)
      println(f(5, 10))

   }

    val data = List(1, 2, 3, 4, 5, 6)
    //使用偏函数来遍历list 使用空格+_
    data.foreach(println _)
    data.foreach(x => println(x))
    def sum(a: Int, b: Int, c: Int) = a + b + c
    println(sum(1, 2, 3))
    val fp_a = sum _
    //直接调用定义sum函数 ，调用它相应的apply函数
    println(fp_a(1, 2, 3))
    println(fp_a.apply(1, 2, 3))
    val fp_b = sum(1, _: Int, 3)
    println(fp_b(2))
    println(fp_b(10))
    data.foreach(println _)
    data.foreach(println)

    def main(args: Array[String]) {
        
    val data = List(1, 2, 3, 4, 5, 6)
    var sum = 0
    data.foreach(sum += _)
    def add(more: Int) = (x: Int) => x + more
    val a = add(1)
    val b = add(9999)
    println(a(10))
    
    println(b(10)