如何创建这个多重数组、哈希组合？

Question

我有 此数据，我需要类似这种类型的输出。我基本上需要拥有所有场地和他们的日期以及与他们相关的所有歌曲...如果有人能想到更好的结构以及如何实现它，我将非常感激...

{ 
["Vector Arena - Auckland Central, New Zealand" => 
    { 
    "2010-10-10" => ["Enter Sandman", "Unforgiven", "And justice for all"]
    }], 
    ["Brisbane Entertainment Centre - Brisbane Qld, Austr..." => 
        { 
        "2010-10-11" => ["Enter Sandman"]
    }]
 }

到目前为止我尝试过这个...并且不确定我是否要搬进来正确的方向..

@venues = Hash.new {|hash, key| hash[key] = 0}
@requests = Request.find_all_by_artist("Metallica")
@requests.each do |request|
  @venues[request.venue] =  request.showdate
end

Answer 1

这是一个有效的解决方案：

result = Hash.new {|h1, k1| h1[k1] = Hash.new{|h2, k2| h2[k2] = []}}
Request.find_all_by_artist("Metallica", 
 :select => "DISTINCT venue, showdate, LOWER(song) AS song"
).each do |req|
  result[req.venue][req.showdate] << req.song.titlecase
end

Answer 2

我认为你的结构不太正确。它应该像

[ 
{"Vector Arena - Auckland Central, New Zealand" => 
    { 
    "2010-10-10" => ["Enter Sandman", "Unforgiven", "And justice for all"]
    }}, 
    }"Brisbane Entertainment Centre - Brisbane Qld, Austr..." => 
        { 
        "2010-10-11" => ["Enter Sandman"]
    }}
 ]

尝试这个代码

@venues = []
      all_venues = Request.find(:all, :select => "distinct venue, showdate")
      all_venues.each do |unique_venue|
        venue_hash = {}
        showdate_hash = {}
        song_lists = []

        requests = Request.find_all_by_venue(unique_venue.venue)  
        requests.each do |each_request|
          song_lists << each_request.song
        end
        showdate_hash[unique_venue.showdate] = song_lists

        venue_hash[unique_venue.venue] = showdate_hash
        @venues << venue_hash
      end

希望你至少明白这个想法。