How to learn spark-shell

How to learn spark-shell, in view of this problem, this article introduces the corresponding analysis and solutions in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

Today I'm going to introduce you to the application of spark-shell.

Spark-shell is a running script for spark. It has initialized sparkContext (sc) and SparkSesssion (Spark)

You can go to the installation path of spark

Bin/spark-shell

The above picture shows that it is correct. Next, you can operate spark.

Note that spark uses the scala language

Val text = sc.textFile ("/ usr/wordcount.txt")

Text.count ()

Run the results as shown. Note that here we are loading local files, not hdfs files

Let's manipulate the hdfs file. Write out the wordcount program

First, upload the file to hdfs

. / hdfs dfs-put / usr/a.txt / user/spark

Then manipulate the data.

Val text = sc.textFile ("hdfs://192.168.153.11:9000/user/spark/a.txt")

Val counts = text.flatMap (line = > line.split ("")) .map (word = > (word, 1)) .reduceByKey (_ + _)

Counts.saveAsTextFile ("hdfs://192.168.153.11:9000/user/spark/wordcount")

The following one is also the demo that calculates PI

The answers to the questions on how to learn spark-shell are shared here. I hope the above content can be of some help to you. If you still have a lot of doubts to be solved, you can follow the industry information channel to learn more about it.