Re: What is the difference between 'except IOError as e:' and 'except IOError, e:'

[Marcus Gnaß]

See also
http://docs.python.org/dev/3.0/whatsnew/2.6.html#pep-3110-exception-handling-changes
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Re: What is the difference between 'except IOError as e:' and 'except IOError, e:'

[MRAB]

Peng Yu wrote:

I don't see any different between the following code in terms of
output. Are they exactly the same ('as' v.s. ',')?

try:
  raise IOError('IOError')
except IOError as e:
  print e

try:
  raise IOError('IOError')
except IOError, e:
  print e


The second form is the old form. Later versions of Python introduced the
first form because it is less confusing.

If you wanted a single 'except' to catch 2 exceptions you would need to
write:

try:
...
except (IOError, OSError):
...

Sometimes people who are new to Python mistakenly write:

try:
...
except IOError, OSError:
...

thinking that that form will catch 2 exceptions, and they'll then be
puzzled when it doesn't work properly.
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Re: What is the difference between 'except IOError as e:' and 'except IOError, e:'

[Steven D'Aprano]

On Tue, 17 Nov 2009 20:28:16 -0600, Peng Yu wrote:

> I don't see any different between the following code in terms of output.
> Are they exactly the same ('as' v.s. ',')?
> 
> try:
>   raise IOError('IOError')
> except IOError as e:
>   print e

This is the preferred syntax. It is used in Python 2.6 and better. It is 
a syntax error in Python 2.5 and older.


> try:
>   raise IOError('IOError')
> except IOError, e:
>   print e

This is the obsolete syntax, used in Python 2.5 and older.


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Steven
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Re: What is the difference between 'except IOError as e:' and 'except IOError, e:'

[Xavier Ho]

On Wed, Nov 18, 2009 at 12:28 PM, Peng Yu  wrote:

> I don't see any different between the following code in terms of
> output. Are they exactly the same ('as' v.s. ',')?
>

Yes, they're exactly the same. However, the syntax with "as" is newer,
introducted in Python 3.x, and eventually backported to 2.6. If you have
used Python 2.5, only the comma syntax would work.

Cheers,
Xav
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What is the difference between 'except IOError as e:' and 'except IOError, e:'

[Peng Yu]

I don't see any different between the following code in terms of
output. Are they exactly the same ('as' v.s. ',')?

try:
  raise IOError('IOError')
except IOError as e:
  print e

try:
  raise IOError('IOError')
except IOError, e:
  print e
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