Machine Learning with R Cookbook - Second Edition

How to do it...

Perform the following steps to operate files stored on HDFS:

1. Initialize the rhdfs package:

        > Sys.setenv(HADOOP_CMD="/usr/bin/hadoop")
        > Sys.setenv(HADOOP_STREAMING="/usr/lib/hadoop-mapreduce/hadoop-        streaming-2.5.0-cdh5.2.0.jar")
        > library(rhdfs)
        > hdfs.init ()  

2. You can then manipulate files stored on HDFS, as follows:
   • hdfs.put: Copy a file from the local filesystem to HDFS:

          > hdfs.put('word.txt', './')  

• hdfs.ls: Read the list of directory from HDFS:

          > hdfs.ls('./')  

• hdfs.copy: Copy a file from one HDFS directory to another:

          > hdfs.copy('word.txt', 'wordcnt.txt') 

• hdfs.move : Move a file from one HDFS directory to another:

          > hdfs.move('wordcnt.txt', './data/wordcnt.txt')

• hdfs.delete: Delete an HDFS directory ...