Json 如何访问属于特定值的嵌套值

我访问一些数据有困难

我有这个档案：

SUPPLIERS = [
{ name: "FunePlus", advitam_grade: 3, works: [ { type: "embalming", price: 350 }, {type: "transport_before_casketing", price: 450} ]},
{ name: "FuneTop", works: [ { type: "graving", price: 10 } ]},
{ name: "FuneTruc", advitam_grade: 5, works: [ { type: "embalming", price: 750 }]},
{ name: "FuneCorp", advitam_grade: 2, works: [ { type: "digging", price: 350 }]}
]



class SelectSupplier
  def self.global_grade(name)

  end
end

SelectSupplier.global_grade("FunePlus")

当我调用方法

global\u grade

时，我想加入一个特定的名称，然后返回相关的值

以下是我想要的输出：

SelectSupplier.global_grade("FunePlus")
 :advitam_grade=>3, :works=>[{:type=>"embalming", :price=>350}, {:type=>"transport_before_casketing", :price=>450}]}

---

你们中有人知道我怎么做吗

您可以使用

Array#find

方法：

SUPPLIERS = [
{ name: "FunePlus", advitam_grade: 3, works: [ { type: "embalming", price: 350 }, {type: "transport_before_casketing", price: 450} ]},
{ name: "FuneTop", works: [ { type: "graving", price: 10 } ]},
{ name: "FuneTruc", advitam_grade: 5, works: [ { type: "embalming", price: 750 }]},
{ name: "FuneCorp", advitam_grade: 2, works: [ { type: "digging", price: 350 }]}
]



class SelectSupplier
  def self.global_grade(name)
      SUPPLIERS.find {|x| x[:name] == name }
  end
end

SelectSupplier.global_grade("FunePlus")

---

这将返回与

名称

参数匹配的第一个哈希值

您可以使用

数组#find

方法：

SUPPLIERS = [
{ name: "FunePlus", advitam_grade: 3, works: [ { type: "embalming", price: 350 }, {type: "transport_before_casketing", price: 450} ]},
{ name: "FuneTop", works: [ { type: "graving", price: 10 } ]},
{ name: "FuneTruc", advitam_grade: 5, works: [ { type: "embalming", price: 750 }]},
{ name: "FuneCorp", advitam_grade: 2, works: [ { type: "digging", price: 350 }]}
]



class SelectSupplier
  def self.global_grade(name)
      SUPPLIERS.find {|x| x[:name] == name }
  end
end

SelectSupplier.global_grade("FunePlus")

---

这将返回与您的

名称

参数匹配的第一个哈希值

@John告诉您如何提取所需的哈希值。如果您希望多次这样做，对于键<代码>名称< /代码>的不同值，您应该考虑一次性构造哈希来加快查找速度。

SUPPLIERS = [
  { name: "FunePlus", advitam_grade: 3, works: [ { type: "embalming", price: 350 }, 
    { type: "transport_before_casketing", price: 450} ]},
  { name: "FuneTop",                    works: [ { type: "graving", price: 10 } ]},
  { name: "FuneTruc", advitam_grade: 5, works: [ { type: "embalming", price: 750 }]},
  { name: "FuneCorp", advitam_grade: 2, works: [ { type: "digging", price: 350 }]}
]

class SelectSupplier
  @supplier_index = SUPPLIERS.each_with_index.with_object({}) { |(g,i),h| h[g[:name]] = i }
  def self.global_grade(name)
    SUPPLIERS[@supplier_index[name]]
  end
end

SelectSupplier.global_grade("FunePlus")
  #=> {:name=>"FunePlus", :advitam_grade=>3, :works=>[{:type=>"embalming", :price=>350},
  #     {:type=>"transport_before_casketing", :price=>450}]}

散列

@supplier\u index

等于以下值

SelectSupplier.instance_variable_get(:@supplier_index)
  #=> {"FunePlus"=>0, "FuneTop"=>1, "FuneTruc"=>2, "FuneCorp"=>3}

---

请注意，我可以用与

供应商

元素（哈希）相等的值构造

@supplier\u index

，但这会增加内存需求（当然，这可能不是问题）。

@John已经告诉您如何提取所需的哈希。如果您希望多次这样做，对于键<代码>名称< /代码>的不同值，您应该考虑一次性构造哈希来加快查找速度。

SUPPLIERS = [
  { name: "FunePlus", advitam_grade: 3, works: [ { type: "embalming", price: 350 }, 
    { type: "transport_before_casketing", price: 450} ]},
  { name: "FuneTop",                    works: [ { type: "graving", price: 10 } ]},
  { name: "FuneTruc", advitam_grade: 5, works: [ { type: "embalming", price: 750 }]},
  { name: "FuneCorp", advitam_grade: 2, works: [ { type: "digging", price: 350 }]}
]

class SelectSupplier
  @supplier_index = SUPPLIERS.each_with_index.with_object({}) { |(g,i),h| h[g[:name]] = i }
  def self.global_grade(name)
    SUPPLIERS[@supplier_index[name]]
  end
end

SelectSupplier.global_grade("FunePlus")
  #=> {:name=>"FunePlus", :advitam_grade=>3, :works=>[{:type=>"embalming", :price=>350},
  #     {:type=>"transport_before_casketing", :price=>450}]}

散列

@supplier\u index

等于以下值

SelectSupplier.instance_variable_get(:@supplier_index)
  #=> {"FunePlus"=>0, "FuneTop"=>1, "FuneTruc"=>2, "FuneCorp"=>3}

---

请注意，我可以用与

供应商

元素（哈希）相等的值构建

@supplier\u index

，但这会增加内存需求（当然，这可能不是问题）。

尝试

选择supplier.global\u grade（“FunePlus”）时会得到什么结果

？尝试选择Supplier.global_grade（“FunePlus”）时会得到什么结果？