如何将JSON转换为哈希，搜索和更改值

Question

我正在尝试处理JSON文件：

{
  "features": {
    "additional-options": true
  },
  "values": {
    "lo-value": 34,
    "hi-value": 554
  },
  "persons": [
    {
      "name": "john",
      "member": true,
      "current": false,
      "sponsor": "pete",
      "profile": "",
      "credits": ["04"],
      "linked": ["philip","guy"],
      "maptools": ["crossfit","soccer","running"]
    },
    {
      "name": "mary",
      "member": true,
      "current": false,
      "sponsor": "judy",
      "profile": "",
      "credits": ["all"],
      "activities": ["swimming","cycling","running"]
    }
  ],
  "data_map": [1122,3234]
}

我希望能够：

• 更新键值对上的值
• 删除键/值
• 删除或插入一个数组值

我已经做了很多事情来解决这个问题。

我的简化代码思路是：

require 'json'

hash = JSON.parse(File.read('test.json'))

# Add key & value or change existing one
def change_key(hash, key, value)
    keys = key.strip(".")
    hash[*keys] = value
end

def add_to_array(hash, key, val)
    keys = key.strip(".")
    hash[*keys] = locate_arr(hash, key).insert(val)
end

# Delete a key and it's value
def del_key(hash, key)
    keys = key.strip(".")
    hash[*keys].delete[-1]
end

def del_from_array(hash, key, val)
    keys = key.strip(".")
    hash[*keys] = locate_arr(hash, key).delete[-1]
end

f = File.write('test.json') ; f.puts JSON.pretty_generate(hash)


change_key(hash, "features.additional-options", false)

del_from_array(hash, "persons.name=mary.activities", "cycling")

add_to_array(hash, "persons.name=mary.activities", "hockey")

del_key(hash, "data_map")

del_key(hash, persons.name=john.profile)

del_key(hash, persons.name=mary.credits)

生成的JSON应该是：

{
  "features": {
    "additional-options": false
  },
  "values": {
    "lo-value": 34,
    "hi-value": 554
  },
  "persons": [
    {
      "name": "john",
      "member": true,
      "current": false,
      "sponsor": "pete",
      "credits": ["04"],
      "linked": ["philip","guy"],
      "maptools": ["crossfit","soccer","running"]
    },
    {
      "name": "mary",
      "member": true,
      "current": false,
      "sponsor": "judy",
      "profile": "",
      "activities": ["swimming", "running","hockey"]
    }
  ]
}

我不确定如何使用这种结构的JSON。

Answer 1

我了解您的JSON可能如下所示：

"{\"features\":{\"additional-options\":true},\"values\":{\"lo-value\":34,\"hi-value\":554},\"persons\":[{\"name\":\"john\",\"member\":true,\"current\":false,\"sponsor\":\"pete\",\"profile\":\"\",\"credits\":[\"04\"],\"linked\":[\"philip\",\"guy\"],\"maptools\":[\"crossfit\",\"soccer\",\"running\"]},{\"name\":\"mary\",\"member\":true,\"current\":false,\"sponsor\":\"judy\",\"profile\":\"\",\"credits\":[\"all\"],\"activities\":[\"swimming\",\"cycling\",\"running\"]}],\"data_map\":[1122,3234]}"

我建议使用OpenStruct来组织数据：

your_struct_name =  JSON.parse(yourJson, object_class: OpenStruct)

然后，您得到了所有想要的东西。对于您显示的操作：

#change_key(hash, "features.additional-options", false)
your_struct_name.features['additional-options'] = false 
#this one above you set in this hash-like manner because of the '-' in the middle of the key. Otherwise you could just do your_struct_name.features.additional_options = false

#del_from_array(hash, "persons.name=mary.activities", "cycling")
your_struct_name.persons.last.activities.delete('swimming')

# or selecting by name:
your_struct_name.persons.select {|person| person.name == 'mary' }.first.activities.delete('swimming')

#add_to_array(hash, "persons.name=mary.activities", "hockey")
your_struct_name.persons.last.activities << 'hockey'

#del_key(hash, "data_map")
your_struct_name.delete_field('data_map')

#del_key(hash, persons.name=john.profile)
...

#del_key(hash, persons.name=mary.credits)
...

然后，进行更改后，可以使用：

your_struct_name.to_h.to_json

您还可以使用该方法as_json来获得与问题所显示的结构非常相似的结构：

your_struct_name.as_json

OpenStruct处理 结构变化的
数据非常好。如果您具有可以“建模”的数据，可以调用的名称，可以预测的某些属性，甚至可以用于此数据的方法，那么建议您创建一个Class来描述此数据，其属性和属性（甚至可以继承自OpenStruct）。然后在这个Class域内工作，创建一个抽象层。这样，您的代码将变得更加健壮和易读。不要忘记创建自动测试！它为您节省了大量时间。

组织和抽象数据的方式，特别是命名实体的方式，对代码质量有很大影响。

有关更多信息，请参见：Object和ActiveData。