utility function for R to make it easier to add to a hash value without checking whether it exists first

gistfile1.rb

class Object
  def add_safe(var,val)
    if val.class == Fixnum
      if self[var].nil?
        self[var] = val
      else
        self[var] = self[var] + val
      end
    else
      if self[var].nil?
        self[var] = [val]
      else
        self[var] = self[var] + [val]
      end
    end
  end
end

class Hash
  def add_safe(var,val)
    super
  end
  alias :add :add_safe  # we've already used this in the code
end