python - 根据Python3中的值传递可选参数

Question

我有一个参数，可以是 None 或 String。如果它是 None，我无法将其作为参数传递，因为该库不支持 None 值也不支持空字符串。该库也不接受字典作为输入。另一方面，我真的不想写这样一个可怕的替代方案!

if lifecycle_policy_name:
    response = client.create_notebook_instance(
        NotebookInstanceName=NotebookInstanceName,
        InstanceType=InstanceType,
        SubnetId=SubnetId,
        SecurityGroupIds=SecurityGroupIds,
        RoleArn=RoleArn,
        Tags=Tags,
        DirectInternetAccess='Disabled',
        VolumeSizeInGB=10,
        RootAccess='Disabled',
        KmsKeyId=kms_key.get('KeyId'),
        LifecycleConfigName=lifecycle_policy_name
    )
else:
    response = client.create_notebook_instance(
        NotebookInstanceName=NotebookInstanceName,
        InstanceType=InstanceType,
        SubnetId=SubnetId,
        SecurityGroupIds=SecurityGroupIds,
        RoleArn=RoleArn,
        Tags=Tags,
        DirectInternetAccess='Disabled',
        VolumeSizeInGB=10,
        RootAccess='Disabled',
        KmsKeyId=kms_key.get('KeyId'),
    )

正如您所猜测的，这是调用 Boto3 api。

Answer 1

您可以尝试使用关键字参数扩展:

kwargs = dict(
    NotebookInstanceName=NotebookInstanceName,
    InstanceType=InstanceType,
    SubnetId=SubnetId,
    SecurityGroupIds=SecurityGroupIds,
    RoleArn=RoleArn,
    Tags=Tags,
    DirectInternetAccess='Disabled',
    VolumeSizeInGB=10,
    RootAccess='Disabled',
    KmsKeyId=kms_key.get('KeyId'),
)

if lifecycle_policy_name:
    kwargs["LifecycleConfigName"] = lifecycle_policy_name
response = client.create_notebook_instance(
    **kwargs
)