[Spark] Word count 練習

先到spark資料夾
cd /opt/spark/

開啟spark-shell
sbin/start-all.sh

開啟spark-shell
bin/spark-shell



建立path到我們要讀的檔案
val path = "/in/123.txt"

把檔案讀進去，sc是SparkContext的縮寫
val file = sc.textFile(path)

file變成了一個RDD，要用collect指令看RDD裡的東西
file.collect



val line1 = file.flatMap(_.split(" "))

line1.collect

val line2 = line1.filter(_ != "")

line2.collect

val line3 = line2.map(s=> (s,1))

line3.collect

val line4 = line3.reduceByKey(_ + _)

line4.collect

line4.take(10)

line4.take(10).foreach(println)


官網一行指令

val wordCounts = file.flatMap(line => line.split(" ")).map(word => (word, 1)).reduceByKey((a, b) => a + b)

wordCounts.collect()


來看看執行狀況
http://[node IP]:4040/jobs/

[參考資料]

https://spark.apache.org/docs/latest/quick-start.html

http://kurthung1224.pixnet.net/blog/post/275207950