ruby - 考虑单个散列键值合并散列数组

Question

我有一个这样的哈希数组。

[
 {"package_details"=>{"name"=>"Package3", "price"=>3000.0, "id"=>"281"},"event_id"=>336},
 {"package_details"=>{"name"=>"2000/-", "price"=>2000.0, "id"=>"280"}, "event_id"=>337}, 
 {"package_details"=>{"name"=>"Package1", "price"=>1000.0, "id"=>"282"},"event_id"=>337},
 {"package_details"=>{"name"=>"Package2", "price"=>2000.0, "id"=>"283"},"event_id"=>337}
]

我希望它是这样的。

[
  {"event_id"=>336, "package_details"=>[
    {"name"=>"Package3", "price"=>3000.0, "id"=>"281"}
  ]},
  {"event_id"=>337, "package_details"=>[
    {"name"=>"2000/-", "price"=>2000.0, "id"=>"280"},
    {"name"=>"Package1", "price"=>1000.0, "id"=>"282"},
    {"name"=>"Package2", "price"=>2000.0, "id"=>"283"}
  ]},
]

Hash 应该根据相等的 event_id 值合并，并且 event 可以有很多包。

我想知道最简单的方法。尽管我能够处理很多 if 和 else 。

Answer 1

为您提供所需功能结果的最简单转换是使用 Enumerable#group_by .

details = [
 {"package_details"=>{"name"=>"Package3","price"=>3000.0,"id"=>"281"},"event_id"=>336},
 {"package_details"=>{"name"=>"2000/-","price"=>2000.0,"id"=>"280"},"event_id"=>337}, 
 {"package_details"=>{"name"=>"Package1","price"=>1000.0,"id"=>"282"},"event_id"=>337},
 {"package_details"=>{"name"=>"Package2","price"=>2000.0,"id"=>"283"},"event_id"=>337}
]

grouped = details.group_by{ |d| d["event_id"] }
#=> {
#=>   336=>[
#=>     {"package_details"=>{"name"=>"Package3", "price"=>3000.0, "id"=>"281"}, "event_id"=>336}],
#=>   337=>[
#=>     {"package_details"=>{"name"=>"2000/-", "price"=>2000.0, "id"=>"280"}, "event_id"=>337},
#=>     {"package_details"=>{"name"=>"Package1", "price"=>1000.0, "id"=>"282"}, "event_id"=>337},
#=>     {"package_details"=>{"name"=>"Package2", "price"=>2000.0, "id"=>"283"}, "event_id"=>337}]
#=> }

有了这个你就可以做到:

grouped.each do |event_id, packages|
  # event_id is the actual value, like 336
  # packages is an array of hashes from your original
end

如果您真的需要您描述的格式，那么您可以这样做:

transformed = details.group_by{ |d| d["event_id"] }.map do |event_id, hashes|
  {
    "event_id"=>event_id,
    "package_details"=>hashes.map{ |h| h["package_details"] }
  }
end    
#=> [
#=>   {"event_id"=>336, "package_details"=>[
#=>     {"name"=>"Package3", "price"=>3000.0, "id"=>"281"}
#=>   ]},
#=>   {"event_id"=>337, "package_details"=>[
#=>     {"name"=>"2000/-", "price"=>2000.0, "id"=>"280"},
#=>     {"name"=>"Package1", "price"=>1000.0, "id"=>"282"},
#=>     {"name"=>"Package2", "price"=>2000.0, "id"=>"283"}
#=>   ]}
#=> ]

以上内容贯穿了分组并将每个键/值对转换(“映射”)为自定义哈希，其内容已根据您的需要进行了修改。