"Counter Hash"

gistfile1.rb

#########################################
#
#  ==Keeps count of number of times key has been added.==
#
#  Use:
#    hsh = Hash.counter_hsh
#    hsh << :foo
#    hsh << :foo << :foo
#    hsh << "foo"
#
#    hsh # { :foo => 3, "foo" => 1 }
#
class Hash
  def << k
    self[k] += 1
    self
  end

  def self.counter_hsh
    Hash.new 0
  end
end