问题
I'm looking for a way to do this without checking for the Python version used.
Please refer to How to write exception reraising code that's compatible with both Python 2 and Python 3? for details about this, since this question extends that one.
Basically, I can generalize this as, "What if the method-based exception raises a language-based exception?"
According to Python try...except comma vs 'as' in except, the following show the right syntax for Python 3 and Python 2:
Python 3:
except MyError as e
Python 2, for versions 2.6+:
except MyError as e
#OR#
except MyError, e
Python 2.5-:
except MyError, e
A little background:
I have a sticky situation in which a script will need to be run on many an ancient Linux machine, in which a variety of different Python versions, including Python 2.5, will be used.
Unfortunately, I have to distribute this as a single, size limited file, which puts some constraints on how much importing I can do.
Also, I'm interested in the case in which one of these may misreport its version, or in code that can be used without necessarily checking for a version. This could be worked around, though, of course.
回答1:
Your only option is to avoid the exception assignment and pull it out of the result for the sys.exc_info() function instead:
try:
# ...
except Exception: # note, no ", e" or "as e"
import sys
e = sys.exc_info()[1]
This'll work on Python 1.5 and up.
However, you'll likely to encounter other incompatibilities and difficulties; writing polyglot Python code (code that works on both Python 2.x and 3.x) is only really workable on Python 2.6 and up.
来源：https://stackoverflow.com/questions/32319317/without-version-checking-or-six-how-can-i-use-except-myerror-e-vs-except