无法用唯一的第一个键确定地更新嵌套词典

Question

我正在尝试创建字典来镜像类中的网络硬件。我嵌套了几个对象属性，以便于将来管理代码：

    self.hw_profile = defaultdict(dict)        
    self.a1k2x_dict = defaultdict(dict)
    self.a1k4_dict = defaultdict(dict)
    self.a1k6_dict = defaultdict(dict)

    self.spa_none = {}

    int_map = {'local_int':"", 'local_pc':"", 'opp_dev_desc':"", 'opp_dev_match':"", 'opp_int':""}

    self.spa_6x1g = {'spa_name':"6XGE-BUILT-IN",
                      'int_type' : 'GigabitEthernet', 
                      'int_quant' : 6,
                      'int_map' : int_map
                    }                  
    self.spa_1x10g = {'spa_name' : 'SPA-1X10GE-L-V2',
                      'int_type' : 'TenGigabitEthernet', 
                      'int_quant' : 1,
                      'int_map' : int_map
                    }
    self.spa_5x1g = {'spa_name' : "SPA-5X1GE-V2", 
                      'int_type' : 'GigabitEthernet', 
                      'int_quant' : 5,
                      'int_map' : int_map
                    }
    self.a1k6_dict = {'slot0':
                        {'spa0': self.spa_1x10g, 
                         'spa1': self.spa_none, 
                         'spa2': self.spa_none,
                         'spa3': self.spa_5x1g},
                       'slot1':
                        {'spa0': self.spa_1x10g, 
                         'spa1': self.spa_1x10g, 
                         'spa2': self.spa_none,
                         'spa3': self.spa_none},
                       'slot2':
                        {'spa0': self.spa_1x10g, 
                         'spa1': self.spa_1x10g, 
                         'spa2': self.spa_none,
                         'spa3': self.spa_none}
                    }

    self.a1k2x_dict = {'slot0':
                        {'spa0': self.spa_6x1g,
                         'spa1': self.spa_5x1g, 
                         'spa2': self.spa_none,
                         'spa3': self.spa_none},
                    }

现在我想使用这些抽象字典并用特定的值填充它们。我试过用.get/.update或简单地使用self.hw_profile['slot0']['spa1'] = x等设置新值

    elif self.hw_name == "cisco-asr-1006":
        self.hw_profile = self.a1k6_dict

    temp_dict1 = {'local_int' : "0/0/0" , 'local_pc':"", 'opp_dev_desc' : "blah1", 'opp_dev_match' : 
                self.re_core1_match, 'opp_int':"" }

    self.hw_profile.get('slot0', {}).get('spa0', {}).get('int_map', {}).update(temp_dict1)


    temp_dict2 = {'local_int' : "1/0/0" , 'local_pc':"", 'opp_dev_desc' : "blah2", 'opp_dev_match' : 
                self.re_core2_match, 'opp_int':"" }

    self.hw_profile.get('slot1', {}).get('spa0', {}).get('int_map', {}).update(temp_dict2)


    temp_dict3 = {'local_int' : "2/0/0" , 'local_pc':"", 'opp_dev_desc' : "blah", 'opp_dev_match' : 
                 self.re_alg_match, 'opp_int':"" }
    self.hw_profile.get('slot2', {}).get('spa0', {}).get('int_map', {}).update(temp_dict3)

我遇到的问题是，无论我做什么，字典中的第一个键似乎都会被忽略，树下的所有分支都会用最后一个值写入，如字典的打印输出所示：

[slot1]
  [spa2]
  [spa3]
  [spa0]
    spa_name = SPA-1X10GE-L-V2
    [int_map]
      opp_dev_desc = opposing ALG
      local_int = 2/0/0
      local_pc =
      opp_dev_match = <_sre.SRE_Pattern object at 0x7f647551b870>
      opp_int =
    int_quant = 1
    int_type = TenGigabitEthernet
  [spa1]
    spa_name = SPA-1X10GE-L-V2
    [int_map]
      opp_dev_desc = blah
      local_int = 2/0/0
      local_pc =
      opp_dev_match = <_sre.SRE_Pattern object at 0x7f647551b870>
      opp_int =
    int_quant = 1
    int_type = TenGigabitEthernet
[slot0]
  [spa2]
  [spa3]
    spa_name = SPA-5X1GE-V2
    [int_map]
      opp_dev_desc = blah
      local_int = 2/0/0
      local_pc =
      opp_dev_match = <_sre.SRE_Pattern object at 0x7f647551b870>
      opp_int =
    int_quant = 5
    int_type = GigabitEthernet
  [spa0]
    spa_name = SPA-1X10GE-L-V2
    [int_map]
      opp_dev_desc = opposing ALG
      local_int = 2/0/0
      local_pc =
      opp_dev_match = <_sre.SRE_Pattern object at 0x7f647551b870>
      opp_int =
    int_quant = 1
    int_type = TenGigabitEthernet
  [spa1]
[slot2]
  [spa2]
  [spa3]
  [spa0]
    spa_name = SPA-1X10GE-L-V2
    [int_map]
      opp_dev_desc = blah
      local_int = 2/0/0
      local_pc =
      opp_dev_match = <_sre.SRE_Pattern object at 0x7f647551b870>
      opp_int =
    int_quant = 1
    int_type = TenGigabitEthernet
  [spa1]
    spa_name = SPA-1X10GE-L-V2
    [int_map]
      opp_dev_desc = opposing ALG
      local_int = 2/0/0
      local_pc =
      opp_dev_match = <_sre.SRE_Pattern object at 0x7f647551b870>
      opp_int =
    int_quant = 1
    int_type = TenGigabitEthernet

我想尽一切办法都试过了。我是遇到了问题还是遗漏了一些基本的东西？你知道吗

Answer 1

您在外部词典中多次引用相同的内部词典。这就是为什么您会看到您所做的修改的最后版本反映在多个地方。你知道吗

正如J.F.Sebastian所评论的，当您将“原型”词典添加到外部词典时（例如使用int_map.copy()或copy.deepcopy(spa_1x10g)），您可以通过复制它们来解决这个问题。这样可以确保引用同一结构的字典的每个位置都获得一个单独的实例，因此可以独立地修改它们。你知道吗

下面是一个简单的示例，它显示了您遇到的相同问题：

inner_dict = {0: 0}
outer_dict = {1: inner_dict, 2: inner_dict}

outer_dict[1][0] = 1
outer_dict[2][0] = 2

print(outer_dict)  # prints {1: {0: 2}, 2: {0: 2}}
print(outer_dict[1] is outer_dict[2] is inner_dict)  # prints True, they're the same dict

这里有一个固定版本的outer_dict定义没有这个问题：

outer_dict = {1: inner_dict.copy(), 2: inner_dict.copy()}

在这个版本中，outer_dict[1]和outer_dict[2]不再引用同一个内部字典，因此可以独立地编辑它们的值。你知道吗

我想您可以不复制引用inner_dict的某个地方，但这可能不值得，因为您很容易在以后编辑代码时出错，并返回到原始问题。你知道吗