gistfile1.rb

  # Returns a copy of self with all +true+ elements removed.
  # [ "a", true, "b", true, "c", true].compact_true #=> [ "a", "b", "c" ]
  #
  def compact_true
    remove_elements(TrueClass)
  end
  
  # Returns a copy of self with all +false+ elements removed.
  # [ "a", false, "b", false, "c", false].compact_true #=> ["a","b","c" ]
  #
  def compact_false
    remove_elements(FalseClass)
  end

  private
  
    def remove_elements(boolean_class)
      self.clone.delete_if { |element| element.is_a?(boolean_class) }
    end