Hadoop Beginner's Guide

Time for action – implementing WordCount using Streaming

Let's flog the dead horse of WordCount one more time and implement it using Streaming by performing the following steps:

1. Save the following file to wcmapper.rb:

   #/bin/env ruby
   
   while line = gets
       words = line.split("\t")
       words.each{ |word| puts word.strip+"\t1"}}
   end

2. Make the file executable by executing the following command:

   $ chmod +x wcmapper.rb
   

3. Save the following file to wcreducer.rb:

   #!/usr/bin/env ruby
   
   current = nil
   count = 0
   
   while line = gets
       word, counter = line.split("\t")
   
       if word == current
           count = count+1
       else
           puts current+"\t"+count.to_s if current
           current = word
           count = 1
       end
   end
   puts current+"\t"+count.to_s

4. Make the file executable by executing the following command:

   $ chmod +x wcreducer.rb ...