英文:
How do I modify the stack list of sys.exc_info()?
问题
我想要从堆栈列表中移除表示装饰器的一些帧，然后再记录它，但是当我尝试访问它时，调试器说没有名为 `stack` 的属性，尽管 PyCharm 显示它：
```py
sys.exc_info()[2].tb_frame.stack # < -- AttributeError，但为什么？
这是我想要做的：
sys.exc_info()[2].tb_frame.stack = sys.exc_info()[2].tb_frame.stack[3:]
<details>
<summary>英文:</summary>
I'd like to remove a couple of frames from the stack list that represent a decorator before logging it, but when I try to get to it, the debugger says that there is no such attribute as `stack` even though PyCharm shows it:
```py
sys.exc_info()[2].tb_frame.stack # <-- AttributeError, but why?
This is what I would like to do:
sys.exc_info()[2].tb_frame.stack = sys.exc_info()[2].tb_frame.stack[3:]
答案1
得分: 3
对于Python 3.8版本中的traceback.tb_frame对象，我看不到stack属性：
try:
raise Exception('test')
except:
cls, e, tb = sys.exc_info()
hasattr(tb.tb_frame, 'stack')
False
你可以通过在回溯(traceback)上追踪tb_next属性，可能在for循环中执行此操作：
try:
do_something()
except Exception as e:
cls, exc, tb = sys.exc_info()
for _ in range(3):
tb_next = tb.tb_next
# 如果没有那么多帧的情况
if not tb_next:
break
tb = tb_next
raise cls.with_traceback(tb)
英文:
FWIW, I can't see an attribute for stack on a traceback.tb_frame object in python 3.8:
try:
raise Exception('test')
except:
cls, e, tb = sys.exc_info()
hasattr(tb.tb_frame, 'stack')
False
You can probably do this in a for loop by tracing the tb_next attribute on the traceback:
try:
do_something()
except Exception as e:
cls, exc, tb = sys.exc_info()
for _ in range(3):
tb_next = tb.tb_next
# in case you don't have that many frames
if not tb_next:
break
tb = tb_next
raise cls.with_traceback(tb)
答案2
得分: 0
stack 属性不是 Python 中 frame 对象的内置属性。看起来 PyCharm 提供了这个属性以方便调试，但它并不属于标准的 Python 库。
要实现从堆栈列表中移除几个帧以达到你期望的结果，你可以使用 traceback 模块直接操作回溯对象。下面是一个例子：
import traceback
try:
# 在这里放置你的代码
pass
except Exception as e:
tb = e.__traceback__
tb = tb.tb_next.tb_next # 跳过两个帧
e.__traceback__ = tb
raise e
在这个例子中，我们访问异常对象 (e) 的 __traceback__ 属性来获取回溯对象。然后我们通过两次访问 tb_next 属性来跳过两个帧，然后将修改后的回溯对象赋值回 __traceback__。最后，我们重新引发异常以保留原始行为。
请注意，以这种方式修改回溯对象并不是一种常见的做法，应该谨慎使用。它可能会产生意想不到的后果，并使调试变得更加困难。
英文:
The stack attribute is not a built-in attribute of the frame object in Python. It seems that PyCharm is providing this attribute as a convenience for debugging purposes, but it is not part of the standard Python library.
To achieve your desired result of removing a couple of frames from the stack list, you can use the traceback module to manipulate the traceback object directly. Here's an example:
import traceback
try:
# Your code here
pass
except Exception as e:
tb = e.__traceback__
tb = tb.tb_next.tb_next # Skip two frames
e.__traceback__ = tb
raise e
In this example, we access the __traceback__ attribute of the exception object (e) to get the traceback object. We then skip two frames by accessing the tb_next attribute twice, and assign the modified traceback object back to __traceback__. Finally, we re-raise the exception to preserve the original behavior.
Note that modifying the traceback object in this way is not a common practice and should be used with caution. It may have unexpected consequences and make debugging more difficult.
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