ruby-map-reduce

Some examples and notes about writing map reduces in ruby to run under Hadoop.

Examples

• Counting Words (got from Big Fast Blog)

Things I've learned

• Running locally without Apache Hadoop

You can test your maps/reduces on your shell prompt by just piping the source data from the source file to the map, sorting its output before piping it to the reduce.

cat my-source-file.txt | ruby map.rb | sort | ruby reduce.rb

• The output of a map

Each output of a map must always be on the format key tab value newline

puts "#{key}\t#{value}"