Does `yield from` have O(1) time complexity?
来源： https://stackoverflow.com/questions/61591596/does-yield-from-have-o1-time-complexity
yield-from
Converting “yield from” statement to Python 2.7 code
问题 I had a code below in Python 3.2 and I wanted to run it in Python 2.7. I did convert it (have put the code of missing_elements in both versions) but I am not sure if that is the most efficient way to do it. Basically what happens if there are two yield from calls like below in upper half and lower half in missing_element function? Are the entries from the two halves (upper and lower) appended to each other in one list so that the parent recursion function with the yield from call and use both
'yield from' inside async function Python 3.6.5 aiohttp
问题 SyntaxError: 'yield from' inside async function async def handle(request): for m in (yield from request.post()): print(m) return web.Response() Used python3.5 before, found pep525, install python3.6.5 and still receive this error. 回答1: You are using the new async / await syntax to define and execute co-routines, but have not made a full switch. You need to use await here: async def handle(request): post_data = await request.post() for m in post_data: print(m) return web.Response() If you
“yield from iterable” vs “return iter(iterable)”
问题 When wrapping an (internal) iterator one often has to reroute the __iter__ method to the underlying iterable. Consider the following example: class FancyNewClass(collections.Iterable): def __init__(self): self._internal_iterable = [1,2,3,4,5] # ... # variant A def __iter__(self): return iter(self._internal_iterable) # variant B def __iter__(self): yield from self._internal_iterable Is there any significant difference between variant A and B? Variant A returns an iterator object that has been
Difference between `return iterator` and `yield from iterator`
问题 I'm trying to implement my own version of itertools.compress , the problem is that i stumbled upon the return type. I mean both of these functions return an iterator, but i think the second one is not considered a generator function because there is no yield statement inside. So my question is, are these two implementations equivalent ? def compress (seq, selectors): from operator import itemgetter fst = itemgetter (0) snd = itemgetter (1) yield from map (fst, filter (snd, zip (seq, selectors
Difference between `return iterator` and `yield from iterator`
I'm trying to implement my own version of itertools.compress , the problem is that i stumbled upon the return type. I mean both of these functions return an iterator, but i think the second one is not considered a generator function because there is no yield statement inside. So my question is, are these two implementations equivalent ? def compress (seq, selectors): from operator import itemgetter fst = itemgetter (0) snd = itemgetter (1) yield from map (fst, filter (snd, zip (seq, selectors))) def compress (seq, selectors): from operator import itemgetter fst = itemgetter (0) snd =
Difference between `yield from foo()` and `for x in foo(): yield x`
问题 In Python most examples of yield from explain it with saying that yield from foo() is similar to for x in foo(): yield x On the other hand it doesn't seem to be exactly the same and there's some magic thrown in. I feel a bit uneasy about using a function that does magic that I don't understand. What do I have to know about the magic of yield from to avoid getting into a situation where the magic does something I don't expect? What advantages does the magic provide, that I should be aware of?
Difference between `yield from foo()` and `for x in foo(): yield x`
In Python most examples of yield from explain it with saying that yield from foo() is similar to for x in foo(): yield x On the other hand it doesn't seem to be exactly the same and there's some magic thrown in. I feel a bit uneasy about using a function that does magic that I don't understand. What do I have to know about the magic of yield from to avoid getting into a situation where the magic does something I don't expect? What advantages does the magic provide, that I should be aware of? When foo() returns a regular iterable, the two are equivalent. The 'magic' comes into play when foo()
Converting “yield from” statement to Python 2.7 code
I had a code below in Python 3.2 and I wanted to run it in Python 2.7. I did convert it (have put the code of missing_elements in both versions) but I am not sure if that is the most efficient way to do it. Basically what happens if there are two yield from calls like below in upper half and lower half in missing_element function? Are the entries from the two halves (upper and lower) appended to each other in one list so that the parent recursion function with the yield from call and use both the halves together? def missing_elements(L, start, end): # Python 3.2 if end - start <= 1: if L[end]