hash_counter.rb

def hash_counter(default=nil)
  Hash.new{ |k,v| k[v] = block_given? ? yield : default }
end

counts = {
  :sl => {
    :absent => hash_counter(0),
    :missing_data => hash_counter { hash_counter(0) },
    :present_data => hash_counter { hash_counter(0) },
  },
  :sm => {
    :absent => hash_counter(0),
    :missing_data => hash_counter { hash_counter(0) },
    :present_data => hash_counter { hash_counter(0) },
  },
  :sv => {
    :absent => hash_counter(0),
    :missing_data => hash_counter { hash_counter(0) },
    :present_data => hash_counter { hash_counter(0) },
  },
  :missing_data => hash_counter(0),
}