On 4/16/2019 4:54 PM, Stefano Borini wrote:
given the following code
def g():
yield 2
yield 3
return 6
for x in g():
print(x)
The output is obviously
2
3
As far as I know, there is currently no way to capture the
StopIteration value when the generator is used in a for loop. Is it
true?
If not, would a syntax like:
for x in g() return v:
print(x)
print(v) # prints 6
be useful? It would be syntactic sugar for (corner cases omitted)
Syntactic sugar should be reserved for fairly common cases, not for
extremely rare cases.
def g():
yield 2
yield 3
return 6
If a for loop user needs to see 6, it should be yielded.
Adding non-None return values to StopIteration is fairly new, and was/is
intended for cases where a generator is not being used as a simple
forward iterator. For such special cases, special code like the
following should be used.
it = iter(g())
while True:
try:
x = next(it)
except StopIteration as exc:
v = exc.value
break
else:
print(x)
print(v)
--
Terry Jan Reedy
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