用scala統計單詞個數一步一步詳解
//先按空格切分
val lines_1 = lines.map(_.split(" "))
//壓平
val lines_2 = lines_1.flatten
//用flatMap 兩步合併成一步
val words= lines.flatMap(_.split(" "))
//將每一個單詞對映為元組
val wordToOne = lines_3.map(x=>(x,1))
val wordToOne = lines_3.map((_,1))
//分組
val grouped = wordToOne.groupBy(_._1)
val grouped_1 = grouped.map(t => (t._1,t._2.size))
//將map轉化成List
val result = grouped_1.toList
//排序
val result_1 = result.sortBy(_._2).reverse
合併為一句
val words = lines.flatMap(_.split(" ")).map((_,1)).groupBy(_._1).map(t=>(t._1,t._2.size)).toList.sortBy(_._2).reverse
val words = lines.flatMap(_.split(" ")).map((_,1)).groupBy(_._1).mapValues(_.size).toList.sortBy(_._2).reverse
val words = lines.flatMap(_.split(" ")).map((_,1)).groupBy(_._1).mapValues(_.foldLeft(0)
(_+_._2)).toList.sortBy(_._2).reverse
從本地讀取檔案
package main.count import scala.io.Source object WordCounts { /* * 從本地讀取檔案統計個數 * */ def main(args: Array[String]): Unit = { val lines=Source.fromFile("d:\\words.txt").getLines().toBuffer //val lines=lines.map(_.split(" ")).flatten.map(t=>(t,1)).groupBy(_._1).map(x=>(x._1,x._2.size)).toList.sortBy(_._2).reverse val lines1=lines.flatMap(_.split(" ")).map((_,1)).groupBy(_._1).map(t=>(t._1,t._2.size)).toList.sortBy(_._2).reverse println(lines1) } }