scala面向函数编程 wordcount练习

面向函数编程

wordcount练习

package scala


import scala.io.{BufferedSource, Source}


object Demo11WordCount {
  def main(args: Array[String]): Unit = {
     //1.读取文件
    val source: BufferedSource = Source.fromFile("data/words.txt")
    //转换成集合
  val list: List[String] = source.getLines().toList
   // println(list)

    //2.将每一行的代码拆分出来，一行转多行

    val str: List[String] = list.flatMap((f:String)=>f.split(","))

    //println(str)

    //3.按照单词进行分组
    //key 是单词，value 是单词的集合

    val group: Map[String, List[String]] = str.groupBy((f:String)=>f)

    //group.foreach(println)


    //4.统计单词数量，也即是统计集合的长度
    val stringToInt: Map[String, Int] = group.map((f: (String, List[String])) => {
      val word: String = f._1
      val count: List[String] = f._2
      val length: Int = count.length
      (word, length)
    })

    stringToInt.foreach(println)


    //缩写
    Source
      .fromFile("data/words.txt")
      .getLines()
      .toList
      .flatMap(_.split(","))
      .groupBy(f => f)
      .mapValues(_.length)


  }
}