使用下划线在具有非结构化键的嵌套JSON中查找特定键的JSON值

import json

def find_value(json_obj, target_key):
    if isinstance(json_obj, dict):
        for key, value in json_obj.items():
            if key == target_key:
                return value
            elif isinstance(value, (dict, list)):
                result = find_value(value, target_key)
                if result is not None:
                    return result
    elif isinstance(json_obj, list):
        for item in json_obj:
            result = find_value(item, target_key)
            if result is not None:
                return result

    return None

# 示例嵌套JSON字符串
nested_json = '''
{
  "name": "John",
  "age": 30,
  "address": {
    "street": "123 Main St",
    "city": "New York",
    "country": "USA"
  },
  "contacts": [
    {
      "type": "email",
      "value": "john@example.com"
    },
    {
      "type": "phone",
      "value": "123-456-7890"
    }
  ]
}
'''

# 解析JSON字符串
json_obj = json.loads(nested_json)

# 查找特定键的值
target_key = "city"
result = find_value(json_obj, target_key)

# 输出结果
if result is not None:
    print(f"The value of '{target_key}' is: {result}")
else:
    print(f"The key '{target_key}' was not found in the JSON.")