Python try...except comma vs 'as' in except

The definitive document is PEP-3110: Catching Exceptions

Summary:

• In Python 3.x, using as is required to assign an exception to a variable.
• In Python 2.6+, use the as syntax, since it is far less ambiguous and forward compatible with Python 3.x.
• In Python 2.5 and earlier, use the comma version, since as isn't supported.

Yes it's legal. I'm running Python 2.6

try:
    [] + 3
except Exception as x:
    print "woo hoo"

>>> 
woo hoo

Update: There is another reason to use the as syntax. Using , makes things a lot more ambiguous, as others have pointed out; and here's what makes the difference. As of Python 2.6, there is multicatch which allows you to catch multiple exceptions in one except block. In such a situation, it's more expressive and pythonic to say

except (exception1, exception2) as e

rather than to say

except (exception1, exception2), e

which would still work