except: 和 except Exception as e 之间的区别:

问题描述

Both the following snippets of code do the same thing. They catch every exception and execute the code in the except: block

Snippet 1 -

try:
    #some code that may throw an exception
except:
    #exception handling code

Snippet 2 -

try:
    #some code that may throw an exception
except Exception as e:
    #exception handling code

What is exactly the difference in both the constructs?

解决方案

In the second you can access the attributes of the exception object:

>>> def catch():
...     try:
...         asd()
...     except Exception as e:
...         print e.message, e.args
... 
>>> catch()
global name 'asd' is not defined ("global name 'asd' is not defined",)

But it doesn't catch BaseException or the system-exiting exceptions SystemExit, KeyboardInterrupt and GeneratorExit:

>>> def catch():
...     try:
...         raise BaseException()
...     except Exception as e:
...         print e.message, e.args
... 
>>> catch()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 3, in catch
BaseException

Which a bare except does:

>>> def catch():
...     try:
...         raise BaseException()
...     except:
...         pass
... 
>>> catch()
>>> 

See the Built-in Exceptions section of the docs and the Errors and Exceptions section of the tutorial for more info.