On Wed, Jun 7, 2017 at 10:00 AM, Rob Gaddi
<rgaddi@highlandtechnology.invalid> wrote:
>
> On 06/06/2017 11:13 PM, Frank Millman wrote:
>>
>> Hi all
>>
>> It would be nice to write a generator in such a way that, in addition to
'yielding' each value, it performs some additional work and then 'returns'
a final result at the end.
>>
>>> From Python 3.3, anything 'returned' becomes the value of the
StopIteration
>>
>> exception, so it is possible, but not pretty.
>>
>> Instead of -
>> my_gen = generator()
>> for item in my_gen():
>> do_something(item)
>> [how to get the final result?]
>>
>> you can write -
>> my_gen = generator()
>> while True:
>> try:
>> item = next(my_gen())
>> do_something(item)
>> except StopIteration as e:
>> final_result = e.value
>>
>> Is this the best way to achieve it, or is there a nicer alternative?
>>
>> Thanks
>>
>> Frank Millman
>
> class MyGeneration:
> def __iter__(self):
> yield from ('people', 'try', 'to', 'put', 'us', 'down')
> self.final = 'talking about'
>
> mygen = MyGeneration()
> for item in mygen:
> print(item)
> print(mygen.final)
Or as a generic wrapper:
class CaptureValue:
def __init__(self, iterable):
self._iter = iter(iterable)
def __iter__(self):
return self
def __next__(self):
try:
return next(self._iter)
except StopIteration as e:
self.value = e.value
raise
capture = CaptureValue(generator())
print(list(capture))
print(capture.value)
--
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