Compute percentages of NOAA stations that are zombies per state

compute-percent-zombies-by-state.rb

# ruby compute-percent-zombies-by-state.rb zombies.csv > percent-zombies-by-state.csv

Record = Struct.new(:num_zombies, :num_not_zombies)

def db_make(filename)
  db = {}
  data = File.read(filename)
  lines = data.split("\n")
  lines.each do |line|
    fields = line.split(",")
    state     = fields[3]
    is_zombie = fields[11] == "true"
    unless db.has_key?(state)
      db[state] = Record.new(0, 0)
    end
    if is_zombie
      db[state].num_zombies += 1
    else
      db[state].num_not_zombies += 1
    end
  end
  db
end

def db_dump(db)
  db.each_pair do |state, r|
    total = r.num_zombies + r.num_not_zombies
    percent = r.num_zombies.to_f / total * 100
    puts "#{state},#{total},#{"%.2f" % percent}"
  end
end

if $0 == __FILE__
  unless ARGV.size == 1
    $stderr.puts "<zombies.csv>"
    exit 1
  end
  db = db_make(ARGV.first)
  db_dump(db)
end