On 10/16/2019 1:18 PM, MRAB wrote:
On 2019-10-16 15:03, Antoon Pardon wrote:
I would like to verify I understand correctly.
It is about the following construct:
try:
statement1
statement2
...
except ():
pass
As far as I understand and my tests seem to confirm this, this
is equivallent to just
statement1
statement2
...
Am I correct or did I miss something?
Since except (): cannot catch anything, the two are externally
equivalent given a particular behavior of the statements. Internally,
the first takes a bit longer unless the irrelevant try-except is
optimized away, but checking for this case would be a waste of time.
What if there's an exception?
Antoon is asking whether the two snippets are equivalent for any
particular behavior of the sequence of statements.
>>> def test_1():
... try:
... print('statement1')
... raise ValueError()
... print('statement2')
... except ():
... pass
... print('statement3')
...
>>> def test_2():
... print('statement1')
If you add raise ValueError() to test with the same snippet behavior
... print('statement2')
... print('statement3')
...
>>> test_1()
statement1
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 4, in test_1
ValueError
The point is that except (): cannot not catch any exception.
>>> test_2()
Then you get the same output.
--
Terry Jan Reedy
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