Carl Johnson wrote:
Certainly, it's an inconsistency compared to generator expressions, but
is it a bug? I know that Python 3000 is making it so that list
comprehension variables don't leak anymore, so I take it that the goal
is to have them be more similar to generator expressions than not. Then
again, maybe there are good reasons for this behavior? My own feeling is
that these two cases should behave the same way, but I could be wrong.
Comprehensions and generator expressions in Py3k are more similar than
they are in 2.x, but they still aren't identical.
[x for x in range(10) if f(x)] is shorthand for:
def _f(itr):
_[1] = []
for x in itr:
if f(x):
_[1].append(x)
return _[1]
expr_result = _f(range(10))
While (x for x in range(10) if f(x)) is shorthand for:
def _g(itr):
for x in itr:
if f(x):
yield x
expr_result = _g(range(10))
From those expansions, I think it's pretty clear that the implicit
generator function in the second case is going to swallow the
StopIteration and treat it as the end of the iteration process, but no
such thing is going to happen with the implicit standard function in the
list comprehension case.
Cheers,
Nick.
--
Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
---------------------------------------------------------------
http://www.boredomandlaziness.org
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