我在我的代码中有这个try块:
try:
do_something_that_might_raise_an_exception()
except ValueError as err:
errmsg = 'My custom error message.'
raise ValueError(errmsg)
严格地说，我实际上引发了另一个ValueError，而不是do_something…()抛出的ValueError，在这种情况下被称为err。如何将自定义消息附加到错误?我尝试以下代码，但失败，由于错误，ValueError实例，不可调用:
try:
do_something_that_might_raise_an_exception()
except ValueError as err:
errmsg = 'My custom error message.'
raise err(errmsg)
当前回答
try:
try:
int('a')
except ValueError as e:
raise ValueError('There is a problem: {0}'.format(e))
except ValueError as err:
print err
打印:
There is a problem: invalid literal for int() with base 10: 'a'
其他回答
使用的错误消息引发新的异常
raise Exception('your error message')
or
raise ValueError('your error message')
在你想要引发它或使用'from'将错误消息附加(替换)到当前异常的地方(Python 3。只支持X):
except ValueError as e:
raise ValueError('your message') from e
引发相同的错误，并在前面添加自定义文本消息。 (编辑-抱歉，实际上和https://stackoverflow.com/a/65494175/15229310一样，为什么有10个(好评)“解决方案”只是不回答张贴的问题?)
try:
<code causing exception>
except Exception as e:
e.args = (f"My custom text. Original Exception text: {'-'.join(e.args)}",)
raise
这只适用于Python 3。您可以修改异常的原始参数并添加自己的参数。
异常会记住创建它时使用的参数。我认为这样您就可以修改异常了。
在函数rerraise中，我们在异常的原始参数前加上我们想要的任何新参数(比如消息)。最后，我们在保留回溯历史的同时重新引发异常。
def reraise(e, *args):
'''re-raise an exception with extra arguments
:param e: The exception to reraise
:param args: Extra args to add to the exception
'''
# e.args is a tuple of arguments that the exception with instantiated with.
#
e.args = args + e.args
# Recreate the exception and preserve the traceback info so that we can see
# where this exception originated.
#
raise e.with_traceback(e.__traceback__)
def bad():
raise ValueError('bad')
def very():
try:
bad()
except Exception as e:
reraise(e, 'very')
def very_very():
try:
very()
except Exception as e:
reraise(e, 'very')
very_very()
输出
Traceback (most recent call last):
File "main.py", line 35, in <module>
very_very()
File "main.py", line 30, in very_very
reraise(e, 'very')
File "main.py", line 15, in reraise
raise e.with_traceback(e.__traceback__)
File "main.py", line 28, in very_very
very()
File "main.py", line 24, in very
reraise(e, 'very')
File "main.py", line 15, in reraise
raise e.with_traceback(e.__traceback__)
File "main.py", line 22, in very
bad()
File "main.py", line 18, in bad
raise ValueError('bad')
ValueError: ('very', 'very', 'bad')
Python 3内置异常有strerror字段:
except ValueError as err:
err.strerror = "New error message"
raise err
这是我在Python 2.7和3中用来修改异常消息的函数。X，同时保留原始的回溯。需要6个
def reraise_modify(caught_exc, append_msg, prepend=False):
"""Append message to exception while preserving attributes.
Preserves exception class, and exception traceback.
Note:
This function needs to be called inside an except because
`sys.exc_info()` requires the exception context.
Args:
caught_exc(Exception): The caught exception object
append_msg(str): The message to append to the caught exception
prepend(bool): If True prepend the message to args instead of appending
Returns:
None
Side Effects:
Re-raises the exception with the preserved data / trace but
modified message
"""
ExceptClass = type(caught_exc)
# Keep old traceback
traceback = sys.exc_info()[2]
if not caught_exc.args:
# If no args, create our own tuple
arg_list = [append_msg]
else:
# Take the last arg
# If it is a string
# append your message.
# Otherwise append it to the
# arg list(Not as pretty)
arg_list = list(caught_exc.args[:-1])
last_arg = caught_exc.args[-1]
if isinstance(last_arg, str):
if prepend:
arg_list.append(append_msg + last_arg)
else:
arg_list.append(last_arg + append_msg)
else:
arg_list += [last_arg, append_msg]
caught_exc.args = tuple(arg_list)
six.reraise(ExceptClass,
caught_exc,
traceback)
