使用IPython的运行单元格魔术执行代码时,捕获异常并中断异常

问题描述

使用IPython的magick命令运行Jupyter单元中存在的某些python命令时,如何捕获错误

In [1]: from IPython import get_ipython
        from IPython.core.magics.namespace import NamespaceMagics
        from IPython.utils.capture import capture_output


In [2]: _nms = NamespaceMagics()
        _Jupyter = get_ipython()
        _nms.shell = _Jupyter.kernel.shell
        cell_capture = capture_output(stdout=True,stderr=True,display=True)

In [3]: cell = "y = z**2"

In [4]: with cell_capture:
            _nms.shell.run_cell(cell)
        
        print("This gets printed")

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-9-5330dcdc6092> in <module>
----> 1 y = z**2

NameError: name 'z' is not defined

This gets printed

除了使用exec运行单元格之外,还有没有一种方法可以让我在遇到NameError(或其他任何Exception)时遇到麻烦?

[编辑]

我已经尝试使用try....catch(但不能为我解决该问题):

In [5]: try:
            with cell_capture:
                _nms.shell.run_cell(cell)
        except Exception:
            raise

        print("Something here")


NameError                                 Traceback (most recent call last)
<ipython-input-29-5330dcdc6092> in <module>
----> 1 y = z**2

NameError: name 'z' is not defined

Something here


编辑2

try:
    with cell_capture:
        print('Inside cell capture here')
        _nms.shell.run_cell(cell)
except NameError:
    print("I'm in NameError")
    raise NameError("something bad happened")

print("Something here")


NameError                                 Traceback (most recent call last)
<ipython-input-33-5330dcdc6092> in <module>
----> 1 y = z**2

NameError: name 'z' is not defined

Something here

解决方法

对InteractiveShell.run_cell()的调用结果是ExecutionResult的一个实例。它具有“ raise_error”方法,该方法“如果成功为False,则重新引发错误,否则不执行任何操作”。您可以捕获该异常,对其进行处理,然后重新引发(如果需要)。

with cell_capture:
    result = get_ipython().run_cell(cell)
    result.raise_error()

https://ipython.readthedocs.io/en/stable/api/generated/IPython.core.interactiveshell.html#IPython.core.interactiveshell.ExecutionResult