python - 如何引发我的异常而不是内置异常？

Question

在某些情况下，我需要引发异常，因为内置异常不适合我的程序。在我定义了我的异常之后，python 引发了我的异常和内置异常，如何处理这种情况？我只想打印我的？

class MyExceptions(ValueError):
    """Custom exception."""
    pass

try:
    int(age)
except ValueError:
    raise MyExceptions('age should be an integer, not str.')

输出:

Traceback (most recent call last):
  File "new.py", line 10, in <module>
    int(age)
ValueError: invalid literal for int() with base 10: 'merry_christmas'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "new.py", line 12, in <module>
    raise MyExceptions('age should be an integer, not str.')
__main__.MyExceptions: age should be an integer, not str.

我想打印这样的东西:

Traceback (most recent call last):
  File "new.py", line 10, in <module>
    int(age)
MyException: invalid literal for int() with base 10: 'merry_christmas'

Answer 1

在引发自定义异常时添加 from None:

raise MyExceptions('age should be an integer, not str.') from None

参见 PEP 409 -- Suppressing exception context获取更多信息。