Python错误:AttributeError:__enter__ [英] Python Error: AttributeError: __enter__

问题描述

当我尝试运行代码时收到属性错误.

I receive the attribute error when I try to run the code.

    with ParamExample(URI) as pe:
    with MotionCommander(pe, default_height=0.3)as mc:

这是发生错误的地方.

This is where the error occurs.

Traceback (most recent call last):
File "test44.py", line 156, in <module>
with ParamExample(URI) as pe:
AttributeError: __enter__

那是我在终端中收到的回溯. 如果您需要查看更多我的代码，请告诉我. 任何帮助表示赞赏，谢谢！

That is the traceback that I receive in my terminal. If you need to see more of my code, please let me know. Any help is appreciated, thank you!

推荐答案

更多代码(特别是ParamExample实现)将不胜感激，但是我假设您缺少__enter__(可能还有__exit__ )在该类上的方法.

More code would be appreciated (specifically the ParamExample implementation), but I'm assuming you're missing the __enter__ (and probably __exit__) method on that class.

在python中使用with块时，with语句中的对象将调用其__enter__方法，运行with中的块，然后调用__exit__(可选地提供异常信息)如果有人提出来的话).因此，如果您在课程上没有定义__enter__，则会看到此错误.

When you use a with block in python, the object in the with statement gets its __enter__ method called, the block inside the with runs, and then the __exit__ gets called (optionally with exception info if one was raised). Thus, if you don't have an __enter__ defined on your class, you'll see this error.

侧面说明:您需要缩进第二个with块，使其实际上位于第一个with块中，或者用

Side note: you need to either indent the second with block so it's actually inside the first, OR replace these two lines with

with ParamExample(URI) as pe, MotionCommander(pe, default_height=0.3) as mc:

与嵌套这两个上下文管理器(with块使用的对象的名称)相同.

which is the same as nesting these two context managers (the name of the objects used by with blocks).

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