List biggest file size by extension on a directory.

biggest_file_by_ext.rb

require 'find'

biggest_file_by_ext = {}
Find.find('.') do |path|
  next if File.directory?(path)
  # get file info
  ext  = File.extname(path)
  next unless ext.length > 0
  # get file size
  size = File.size(path)
  # compare & store in hash
  if biggest_file_by_ext.key?(ext)
    if size > biggest_file_by_ext[ext]
      biggest_file_by_ext[ext] = size
    end
  else
    biggest_file_by_ext[ext] = size
  end
end

# print results
biggest_file_by_ext.each do |key, value|
  puts "#{key}: #{(value/1024.0/1024.0).round} MB"
end