arrays - 如何在Ruby中按其中的项目将数组分组

Question

假设我有一个数组：

array = [{"account_id"=>"01", "ad"=>"1"},
{"account_id"=>"05", "ad"=>"2"},
{"account_id"=>"05", "ad"=>"3"},
{"account_id"=>"01", "ad"=>"2"},
{"account_id"=>"10", "ad"=>"3"},
{"account_id"=>"04", "ad"=>"4"}]

我如何将它分成按 account_id 划分的组，例如

l1 = [{"account_id"=>"01", "ad"=>"1"},{"account_id"=>"01", "ad"=>"2"}]
l2 = [{"account_id"=>"05", "ad"=>"2"},{"account_id"=>"05", "ad"=>"3"}]
....

然后将列表一起返回。

我怎样才能做到这一点？是否有任何现有的 API？此外，我正在考虑使用列表列表之类的数据结构（就像List<List<Map<String, String>>>在 Java 中一样？对不起，我是 Ruby 新手），但如果有更好的呈现方式，请告诉我。谢谢

Answer 1

array = [{"account_id"=>"01", "ad"=>"1"},
         {"account_id"=>"05", "ad"=>"2"},
         {"account_id"=>"05", "ad"=>"3"},
         {"account_id"=>"01", "ad"=>"2"},
         {"account_id"=>"10", "ad"=>"3"},
         {"account_id"=>"04", "ad"=>"4"}]


p array.group_by { |h| h['account_id']}

结果

{"01"=>[{"account_id"=>"01", "ad"=>"1"}, {"account_id"=>"01", "ad"=>"2"}], "05"=>[{"account_id"=>"05", "ad"=>"2"}, {"account_id"=>"05", "ad"=>"3"}], "10"=>[{"account_id"=>"10", "ad"=>"3"}], "04"=>[{"account_id"=>"04", "ad"=>"4"}]}

或者你可能会得到如下结果

array.group_by { |h| h['account_id']}.values.each do |value|
  p value
end

结果

[{"account_id"=>"01", "ad"=>"1"}, {"account_id"=>"01", "ad"=>"2"}]
[{"account_id"=>"05", "ad"=>"2"}, {"account_id"=>"05", "ad"=>"3"}]
[{"account_id"=>"10", "ad"=>"3"}]
[{"account_id"=>"04", "ad"=>"4"}]