无法访问其中包含列表的嵌套Python字典

Question

我有下面嵌套的字典：

facter_networking: {"domain": "mylab.com", "fqdn": "mylab.com", "hostname": "mylab", "interfaces": {"ens192": {"bindings": [{"address": "20.9.8.1", "netmask": "255.255.255.221", "network": "20.33.50.62"}], "ip": "20.67.83.48", "mac": "00:00:06:0:e0:d6", "mtu": 1500, "netmask": "255.255.255.224", "network": "20.67.83.48"}, "ens224": {"bindings": [{"address": "20.67.83.48", "netmask": "20.67.83.48", "network": "20.67.83.48"}], "ip": "20.67.83.48", "mac": "20.67.83.48", "mtu": 1500, "netmask": "255.255.255.224", "network": "20.67.83.48"}, "lo": {"bindings": [{"address": "127.0.0.1", "netmask": "255.0.0.0", "network": "127.0.0.0"}], "ip": "127.0.0.1", "mtu": 65536, "netmask": "255.0.0.0", "network": "127.0.0.0"}}, "ip": "20.67.83.48", "mac": "00:00:00:9d:8f:d7", "mtu": 1500, "netmask": "255.255.255.224", "network": "20.67.83.48", "primary": "ens224"}

我可以读取大多数键值，但其中一些我不能。

例如：

print(myfile['facter_networking']['domain']) - it works.
print(myfile['facter_networking']['fqdn']) - it works.
print(myfile['facter_networking']['hostname'])    - it works.

然而，如果我这样做了。

print(myfile['facter_networking']['interfaces']['ens192']['bindings']['address']) - It doens't work.

另一方面，如果我这样做了：

print(myfile['facter_networking']['interfaces']

我得到了结果：

{"ens192": {"bindings": [{"address": "20.9.8.1", "netmask": "255.255.255.221", "network": "20.33.50.62"}], "ip": "20.67.83.48", "mac": "00:00:06:0:e0:d6", "mtu": 1500, "netmask": "255.255.255.224", "network": "20.67.83.48"}, "ens224": {"bindings": [{"address": "20.67.83.48", "netmask": "20.67.83.48", "network": "20.67.83.48"}], "ip": "20.67.83.48", "mac": "20.67.83.48", "mtu": 1500, "netmask": "255.255.255.224", "network": "20.67.83.48"}, "lo": {"bindings": [{"address": "127.0.0.1", "netmask": "255.0.0.0", "network": "127.0.0.0"}], "ip": "127.0.0.1", "mtu": 65536, "netmask": "255.0.0.0", "network": "127.0.0.0"}}, "ip": "20.67.83.48", "mac": "00:00:00:9d:8f:d7", "mtu": 1500, "netmask": "255.255.255.224", "network": "20.67.83.48", "primary": "ens224"}

你知道如何访问上面的这些值吗？

Answer 1

快速修复：您的问题出在访问最后一个嵌套字典"address“。因为它在成为字典之前是嵌套在列表中的，所以你应该像这样得到它：

myfile['facter_networking']['interfaces']['ens192']['bindings'][insert desired index here]['address']

更好的修复了：然而，你目前有一个巨大的设计问题。在dicts中嵌套dicts在dicts中的列表中嵌套dicts是一个嵌套地狱，它使调试正在发生的任何事情变得更加困难，从而阻止了您有效地编码。幸运的是，python是一种面向对象的语言！您可以将大多数字典替换为专用对象，有效地更好地管理您的代码，并减少将来发生类似错误的可能性。

Answer 2

正如评论部分所说，{"bindings": [{"address"是一个列表。而且，和往常一样，如果您尝试使用索引访问空列表，它将抛出异常。相反，循环遍历它，以便在列表为空的情况下得到空列表作为结果

In [66]: [i["address"] for i in myfile['facter_networking']['interfaces']['ens192']['bindings']]
Out[66]: ['20.9.8.1']

Answer 3

问题是，您试图像访问字典一样访问列表：

...{"bindings": [{"address": "20.9.8.1...

访问您需要的地址

....["bindings"][0]["address"]