按天分组Mongoid对象

Question

在控制台中玩了很多次之后,我想出了这种方法,可以在它们发生的那一天将类似activerecord的(Mongoid)对象分组.我不确定这是实现这一目标的最佳方式,但它确实有效.有没有人有更好的建议,或者这是一个好方法吗？

#events is an array of activerecord-like objects that include a time attribute
events.map{ |event|
  # convert events array into an array of hashes with the day of the month and the event
  { :number => event.time.day, :event => event }
}.reduce({}){ |memo,day|
  # convert this into a hash with arrays of events keyed by their day or occurrance
  ( memo[day[:number]] ||= [] ) << day[:event]
  memo
}

=>  {
      29 => [e1, e2],
      28 => [e3, e4, e5],
      27 => [e6, e7],
      ...
    }

谢谢!

Answer 1

经过Forrst的更多思考和一些帮助,我想出了这个:

events.inject({}) do |memo,event|
  ( memo[event.time.day] ||= [] ) << event
  memo
end

显然是Rails monkeypatches使用#group_by方法可以这样工作:

events.group_by { |event| event.time.day }