scala实现wordCount

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题目

scala实现wordcount

环境

IDEA 版本： IntelliJ IDEA 2018.2.5 x64

实现

word.txt

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hadoop	hadoop	hadoop	
word	world	world
pig	hive	word	hive	pig

WordCountApp.scala

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import scala.io.Source

/**
  * 使用scala实现一个wc小程序
  */
object WordCountApp {

  def main(args: Array[String]): Unit = {
    //文件路径
    val filePath = "D:/word.txt"
    //文件编码
    val codec = "utf-8"
    //打开文件
    val file = Source.fromFile(filePath, codec)  
    val wc = file
      .getLines() // ["hadoop	hadoop	hadoop","word	world	world"....]
      
      .flatMap(_.split("\t")) //["hadoop","hadoop","hadoop","word"...
      
      .toList 	//List(hadoop, hadoop, hadoop,...
      
      .map((_, 1)) //List((hadoop,1), (hadoop,1), (hadoop,1), (word,1),...
      
      .groupBy((_._1)) //Map(world -> List((world,1), (world,1)),...
      
      .mapValues(_.size) //Map(world -> 2, hadoop -> 3, hive -> 2, word -> 2, pig -> 2)
    println(wc)
    
    // 关闭文件
    file.close()
  }
    
}

结果

源码

WordCountApp.scala