python - 解析嵌套的 Python 字典

Question

我有一个嵌套字典，我正在尝试解析它，但似乎不知道如何访问第三级项目。感谢帮助这是我的字典

{
    "FunctionName": "RDSInstanctStart",
    "LastModified": "2018-03-24T07:19:56.792+0000",
    "MemorySize": 128,
    "Environment": {
        "Variables": {
            "DBInstanceName": "test1234"
        }
    },
    "Version": "$LATEST",
    "Role": "arn:aws:iam::xxxxxxx:role/lambda-start-RDS",
    "Timeout": 3,
    "Runtime": "python2.7",
    "TracingConfig": {
        "Mode": "PassThrough"
    },
    "CodeSha256": "tBdB+UDA9qlONGb8dgruKc6Gc82gvYLQwdq432Z0118=",
    "Description": "",
    "VpcConfig": {
        "SubnetIds": [],
        "SecurityGroupIds": []
    },
    "CodeSize": 417,
    "FunctionArn": "arn:aws:lambda:us-east-1:xxxxxxxx:function:RDSInstanctStart",
    "Handler": "lambda_function.lambda_handler"
}

我正在尝试访问键“Variables”的值到目前为止，这是我的代码:

try:           

 for evnt in funcResponse['Environment']['Variables']['DBInstanceName']:
            print (evnt[0])
except ClientError as e:
        print(e)

我得到的结果是

t
e
s
t
1
2
3
4    

如果我没有给出 envt 变量的索引，我会得到一个类型错误。

Answer 1

funcResponse['Environment']['Variables']['DBInstanceName'] 是一个单个字符串，但您正在遍历它。字符串是单个字符的序列。

如果您这样做，您会得到相同的结果:for character in "test1234": print(character[0])(并且您可以删除 [0]索引也是如此，因为 character 就像其中包含单个字符的字符串)。

不要循环，只打印:

evnt = funcResponse['Environment']['Variables']['DBInstanceName']
print(evnt)

如果您想打印所有 环境变量，那么您必须遍历 funcResponse['Environment']['Variables'] 字典的项目:

for name, value in funcResponse['Environment']['Variables'].items():
    print(name, value, sep=': ')

无论如何，funcResponse['Environment']['Variables'] 只是一个字典。在末尾添加 ['DBInstanceName'] 将为您提供 'DBInstanceName' 键的值。