1.to_proc

class Array
  def to_proc
    proc { |receiver| receiver.send *self }
  end
end


[ 'Hello', 'Goodbye' ].map &[ :+, ' BeiJing!' ]

#=> ["Hello BeiJing!", "Goodbye BeiJing!"]

receiver -> [ ‘Hello‘, ‘Goodbye‘ ]

*self -> [ :+, ‘ BeiJing!‘ ]

2.map(&:key)

order_records = OrderRecord.all(:all, :limit => 10)

order_records.map(&:order_no)

#=> ["20140627141050-5096zG", "20140627143533-90bm9v", "20140627143648-2sJQxR", "20140627161046-UE0y07", "20140627161456-16GGT1", "20140627161707-58Lc3t", "20140627173915-0mI1Ji", "20140627175248-31YTtk", "20140627180802-s487cX", "20140717112957-eQ993g"]

有趣的程序