daily_royalty_upload.rb

File.open('foo_sorted_reduced.tab', 'w:UTF-8') { |f|
    File.open('foo_sorted.tab', 'r:UTF-8').each_line do |line|
      parts = line.strip.split("\t")
      song_id = parts[0]
      artist = parts[1]
      title = parts[2]
      date = parts[3]
      country = parts[4]
      if last_song_id == -1
        last_song_id = song_id
        last_artist = artist
        last_title = title
        last_date = date
        last_country = country
      end

      if last_song_id == song_id &&
          last_artist.casecmp(artist) == 0 &&
          last_title.casecmp(title) == 0 &&
          last_date.casecmp(date) == 0 &&
          last_country.casecmp(country) == 0
        song_id_country_count += 1
        next
      end

      #output the counts for the previous group
      day = last_date[-2, 2]
      f.printf("%s\t%s\t%s\t%s\t%d\t%s\n", last_song_id,
               last_artist,
               last_title,
               day,
               song_id_country_count,
               last_country)

      last_song_id = song_id
      last_artist = artist
      last_title = title
      last_date = date
      last_country = country
      song_id_country_count = 1
    end
    #output the counts for the last group
    day = last_date[-2, 2]
    f.printf("%s\t%s\t%s\t%s\t%d\t%s\n", last_song_id,
             last_artist,
             last_title,
             day,
             song_id_country_count,
             last_country)
  }