scala函数式编程初体验 ==> 用scala函数实现 WordCount

//定义一个字符串集合

scala> val lines = List("hadoop,hive,spark,hue,mapreduce"," ","hadoop,hue","hdfs, , ,hive","","hadoop,spark")
lines: List[String] = List(hadoop,hive,spark,hue,mapreduce, " ", hadoop,hue, hdfs, , ,hive, "", hadoop,spark)

//功能1 :(不算空格和空串)统计一下集合中总共有多少个单词?

scala> lines.flatMap(_.split(",")).filter(_.trim.nonEmpty).map((_,1)).map(_._2).reduce(_+_)
res164: Int = 11

//功能2 : 分别统计每一个单词出现的次数

scala> lines.flatMap(_.split(",")).filter(_.trim.nonEmpty).groupBy(_.toString).mapValues(_.length).foreach(println)
(mapreduce,1)
(hue,2)
(hadoop,3)
(spark,2)
(hive,2)
(hdfs,1)

 

posted @ 2019-03-14 17:06  Rabbit624  阅读(263)  评论(0编辑  收藏  举报