Question

我有这段代码，而且效果很好

    require "date"
        @past = []
        @future = []

    @artist = Artist.find(2)

    def sort_by_date(artist)
        artist.events.each do |event|
            if event.date < DateTime.now
                @past << event.id
            else
                @future << event.id
            end
        end
    end

    def event_title(arr)
        arr.each do |event_id|
            e = Event.find(event_id)
            artist_names = []

            e.artists.each do |artist|
                unless artist.name == @artist.name
                    artist_names << artist.name
                end
            end

            puts "#{e.name} with #{artist_names.join(", ")} at #{(Venue.find(e.venue_id)).name}"
        end
    end

  sort_by_date(@artist)
  puts "Upcoming Events: "
  event_title(@future)
  puts "Past Events: "
  event_title(@past)

我想将此操作包装到模块中，但我无法理解如何正确地将artist_id传递给它。使用此命令rails runner app/modules/artist_event_sort.rb，我收到此错误：``＆＃39 ;: undefined method sort_by_date' for SortedArtistEvents:Module (NoMethodError)。在我尝试将整个操作包装到一个模块之前，sort_by_date和event_title这两种方法正常运行，因此我知道我错过了什么。

module SortedArtistEvents
    require "date"
    attr_accessor :artist_id
    def initialize(artist_id)
        @past = []
        @future = []
        @artist = Artist.find(artist_id)
    end


    def sort_by_date(artist)
        artist.events.each do |event|
            if event.date < DateTime.now
                @past << event.id
            else
                @future << event.id
            end
        end
    end

    def event_title(arr)
        arr.each do |event_id|
            e = Event.find(event_id)
            artist_names = []

            e.artists.each do |artist|
                unless artist.name == @artist.name
                    artist_names << artist.name
                end
            end

            puts "#{e.name} with #{artist_names.join(", ")} at #{(Venue.find(e.venue_id)).name}"

        end
    end

  sort_by_date(@artist)
  puts "Upcoming Events: "
  self.event_title(@future)
  puts "Past Events: "
  event_title(@past)
end

class LetsSort
  include SortedArtistEvents
end
test_artist_sort = LetsSort.new(2)

Answer 1

看起来这里有一些错误。您正在尝试初始化模块，您只能初始化一个类，例如class SortedArtistEvents。

如果你有这个：

module Foo
  def bar; end
end

bar只能通过包含或扩展Foo的模块或类来访问。如果出现错误undefined method sort_by_date' for SortedArtistEvents:Module，则必须执行

module SortedArtistsEvents
  def self.sort_by_date; end
end

获取SortedArtistsEvents.sort_by_date

等行为

将在Rails环境中运行的代码包装到模块中

1 个答案: