gistfile1.rb

require 'rubygems'
require 'learn_mapreduce'

mr = MapReduce.new

mr.map do |record|
   emit(record[0], 1)
end

mr.reduce do |key, list_of_values|
   count = list_of_values.inject { |sum,i| sum + i }
   emit([key, count])
end

data = [
   ["Jim", "Sue"],
   ["Sue", "Jim"],
   ["Lin", "Joe"],
   ["Joe", "Lin"],
   ["Jim", "Kai"],
   ["Kai", "Jim"],
   ["Jim", "Lin"],
   ["Lin", "Jim"]
]

(emitted, shuffled, output) = mr.run(data)

output.each do |value|
   puts value.inspect
end