使用Ruby从多个哈希数组中构建一个哈希

Question

我有一个哈希数组：

[{:key=>"RepositoryKey", :value=>"6958127"}, 
{:key=>"Guid", :value=>"006444a2-3ea1-4b64-81b8-51ce4756d337"}, 
{:key=>"Association_Guid", :value=>"05500000-93ba-4898-8308-444a25df7eb6"},
{:key=>"Association_Type", :value=>"Association"},
{:key=>"Association_Name", :value=>"Hancock Wellness Center"}, 
{:key=>"Image_Guid", :value=>nil}, 
{:key=>"Image_Type", :value=>"StoredFile"}]

这来自外部源，我需要将某些值组合成一个哈希。例如，我想从上面的数组中RepositoryKey，Guid和Association_Type。我最终想要这样的东西：

hash = {"RepositoryKey" => "6958127", 
        "Guid" => "006444a2-3ea1-4b64-81b8-51ce4756d337", 
        "Association_Type" => "Association"}

使用Ruby 2.0.0的最佳方式是什么？

Answer 1

如果您想要数组中的某些特定项目，则如下所示：

array_of_hash = [
         {:key=>"RepositoryKey", :value=>"6958127"}, 
         {:key=>"Guid", :value=>"006444a2-3ea1-4b64-81b8-51ce4756d337"}, 
         {:key=>"Association_Guid", :value=>"05500000-93ba-4898-8308-444a25df7eb6"},
         {:key=>"Association_Type", :value=>"Association"},
         {:key=>"Association_Name", :value=>"Hancock Wellness Center"}, 
         {:key=>"Image_Guid", :value=>nil}, 
         {:key=>"Image_Type", :value=>"StoredFile"}
       ]

array = ["RepositoryKey", "Guid", "Association_Type"]

Hash[array_of_hash.select { |h| array.include?(h[:key]) }.map(&:values)]
# => {"RepositoryKey"=>"6958127",
#     "Guid"=>"006444a2-3ea1-4b64-81b8-51ce4756d337",
#     "Association_Type"=>"Association"}

如果您想要完整哈希

Hash[array_of_hash.map(&:values)]
# => {"RepositoryKey"=>"6958127",
#     "Guid"=>"006444a2-3ea1-4b64-81b8-51ce4756d337",
#     "Association_Guid"=>"05500000-93ba-4898-8308-444a25df7eb6",
#     "Association_Type"=>"Association",
#     "Association_Name"=>"Hancock Wellness Center",
#     "Image_Guid"=>nil,
#     "Image_Type"=>"StoredFile"}

如果您使用的是Ruby 2.1版本

array_of_hash.map(&:values).to_h

奖金：

如果每个内部哈希的键数多于示例1，并且您希望获得:key和:value的值，则写如下：

array_of_hash.map { |h| h.values_at(:key, :value) }.to_h

Answer 2

早期答案的变体：

<强>代码

arr.each_with_object({}) { |h,g| g[h.values.first] = h.values.last }
   .select { |k,_| target.include?(k) }

<强>演示

arr = [
         {:key=>"RepositoryKey", :value=>"6958127"}, 
         {:key=>"Guid", :value=>"006444a2-3ea1-4b64-81b8-51ce4756d337"}, 
         {:key=>"Association_Guid", :value=>"05500000-93ba-4898-8308-444a25df7eb6"},
         {:key=>"Association_Type", :value=>"Association"},
         {:key=>"Association_Name", :value=>"Hancock Wellness Center"}, 
         {:key=>"Image_Guid", :value=>nil}, 
         {:key=>"Image_Type", :value=>"StoredFile"}
       ]

target = ["RepositoryKey", "Guid", "Association_Type"]

arr.each_with_object({}) { |h,g| g[h.values.first] = h.values.last }
   .select { |k,_| target.include?(k) }
  #=> {"RepositoryKey"=>"6958127",
  #    "Guid"=>"006444a2-3ea1-4b64-81b8-51ce4756d337",
  #    "Association_Type"=>"Association"} 

Answer 3

试试这个

array = [{:key=>"RepositoryKey", :value=>"6958127"}, 
         {:key=>"Guid", :value=>"006444a2-3ea1-4b64-81b8-51ce4756d337"}, 
         {:key=>"Association_Guid", :value=>"05500000-93ba-4898-8308-444a25df7eb6"},
         {:key=>"Association_Type", :value=>"Association"},
         {:key=>"Association_Name", :value=>"Hancock Wellness Center"}, 
         {:key=>"Image_Guid", :value=>nil}, 
         {:key=>"Image_Type", :value=>"StoredFile"}]
hash = Hash[array.map{|h| [h[:key],h[:value]]}]
#=> {"RepositoryKey"=>"6958127", "Guid"=>"006444a2-3ea1-4b64-81b8-51ce4756d337", "Association_Guid"=>"05500000-93ba-4898-8308-444a25df7eb6", "Association_Type"=>"Association", "Association_Name"=>"Hancock Wellness Center", "Image_Guid"=>nil, "Image_Type"=>"StoredFile"}

两个世界中最好的完整哈希，你可以拒绝你以后不想要的值

wanted_values = ["RepositoryKey", "Guid", "Association_Type"]
hash.reject{|k,v| !wanted_values.include?(k)}
#=>{"RepositoryKey"=>"6958127", "Guid"=>"006444a2-3ea1-4b64-81b8-51ce4756d337","Association_Type"=>"Association"}
hash
#=>=> {"RepositoryKey"=>"6958127", "Guid"=>"006444a2-3ea1-4b64-81b8-51ce4756d337", "Association_Guid"=>"05500000-93ba-4898-8308-444a25df7eb6", "Association_Type"=>"Association", "Association_Name"=>"Hancock Wellness Center", "Image_Guid"=>nil, "Image_Type"=>"StoredFile"}

Answer 4

array_of_hash = [
         {:key=>"RepositoryKey", :value=>"6958127"}, 
         {:key=>"Guid", :value=>"006444a2-3ea1-4b64-81b8-51ce4756d337"}, 
         {:key=>"Association_Guid", :value=>"05500000-93ba-4898-8308-444a25df7eb6"},
         {:key=>"Association_Type", :value=>"Association"},
         {:key=>"Association_Name", :value=>"Hancock Wellness Center"}, 
         {:key=>"Image_Guid", :value=>nil}, 
         {:key=>"Image_Type", :value=>"StoredFile"}
       ]

array = ["RepositoryKey", "Guid", "Association_Type"]

array_of_hash.select{|h| array.include? h[:key]}.map{|h| 
                     Hash[*h.values]}.reduce Hash.new, :merge
#=> {"RepositoryKey"=>"6958127", "Guid"=>"006444a2-3ea1-4b64-81b8-51ce4756d337", "As#ociation_Type"=>"Association"}