itertools

问题 Ultimately I need to make info from the Spotify API available to an app that will display "current song" info, including cue time. So will need to be continuously polling the API, as well as updating the data source the App is polling. I'm still trying to wrap my head around thinking of data in terms of streams as opposed to files. So I came up with this little experiment for how a file can be continuously updated: import itertools for i in itertools.count(start=0, step=1): f = open('info.txt

问题 Ultimately I need to make info from the Spotify API available to an app that will display "current song" info, including cue time. So will need to be continuously polling the API, as well as updating the data source the App is polling. I'm still trying to wrap my head around thinking of data in terms of streams as opposed to files. So I came up with this little experiment for how a file can be continuously updated: import itertools for i in itertools.count(start=0, step=1): f = open('info.txt

问题 I have these two lists: boys = [1,2,3] girls = [1,2,3] How would you build all possible (monogamous) pairings [boy, girl] ? With only 3 of both boys and girls , I think this is the list of all the possible pairings: [ [[1,1], [2,2], [3,3]], [[1,1], [2,3], [3,2]], [[1,2], [2,1], [3,3]], [[1,2], [2,3], [3,2]], [[1,3], [2,1], [3,2]], [[1,3], [2,2], [3,1]] ] How would you do it in general (in above format)? This is what I've been able to come up ... pairs = list(itertools.product(boys, girls))

问题 I'm trying to do something like this: import asyncio from itertools import islice async def generate_numbers(n): for x in range(n): yield x async def consume_numbers(n): async for x in generate_numbers(n): print(x) async def consume_some_numbers(n,m): async for x in islice(generate_numbers(n),m): #<-- This doesn't work. islice doesn't recognize async iterators as iterators. print(x) loop = asyncio.get_event_loop() loop.run_until_complete(consume_numbers(10)) loop.run_until_complete(consume

问题 I have two lists [1,2,3,4] and [1,2,3] I would like to sum these to give me the following: [1,3,5,7] . This was done by doing 1+0=1 , 2+1=3 , 3+2=5 and 4+3=7 . I understand that itertools.zip_longest would do this, but it would fill the mismatch in length with 0 at the end, giving me [2,3,6,4] and not the value I want. I would like the mismatch in length to be solved by filling the first length with zero. 回答1: The built-in reversed() function could be used to do it like this: from itertools

问题 I am dealing with lists ls that look like the following: ls = ['y4','j8','Le1','Retx3','MNxe4','Xe4','Xf4','Xe5'] Given one such list, I am trying to find out if it contains 3 consecutive elements that match the following pattern: 3 consecutive elements starting with the letter X , and having the same length (here 3). And their ending digits may only correspond to either of the following cases: denote the ending digit of the first found element by n , then the allowed sequences of the 3

问题 I am dealing with lists ls that look like the following: ls = ['y4','j8','Le1','Retx3','MNxe4','Xe4','Xf4','Xe5'] Given one such list, I am trying to find out if it contains 3 consecutive elements that match the following pattern: 3 consecutive elements starting with the letter X , and having the same length (here 3). And their ending digits may only correspond to either of the following cases: denote the ending digit of the first found element by n , then the allowed sequences of the 3

问题 Edited: I was looking at the type annotations of the built-in zip() function. I understand that overload (in the context of type checking), can modify the behaviour of a function depending on the type of parameters it's given. @overload def zip(__iter1: Iterable[_T1]) -> List[Tuple[_T1]]: ... @overload def zip(__iter1: Iterable[_T1], __iter2: Iterable[_T2]) -> List[Tuple[_T1, _T2]]: ... @overload def zip(__iter1: Iterable[_T1], __iter2: Iterable[_T2], __iter3: Iterable[_T3]) -> List[Tuple[_T1

问题 Edited: I was looking at the type annotations of the built-in zip() function. I understand that overload (in the context of type checking), can modify the behaviour of a function depending on the type of parameters it's given. @overload def zip(__iter1: Iterable[_T1]) -> List[Tuple[_T1]]: ... @overload def zip(__iter1: Iterable[_T1], __iter2: Iterable[_T2]) -> List[Tuple[_T1, _T2]]: ... @overload def zip(__iter1: Iterable[_T1], __iter2: Iterable[_T2], __iter3: Iterable[_T3]) -> List[Tuple[_T1

问题 I'm am trying to get all possible combinations of 11 values repeated 80 times but filter out cases where the sum is above 1. The code below achieves what I'm trying to do but takes days to run: import numpy as np import itertools unique_values = np.linspace(0.0, 1.0, 11) lst = [] for p in itertools.product(unique_values , repeat=80): if sum(p)<=1: lst.append(p) The solution above would work but needs way too much time. Also, in this case I would have to periodically save the 'lst' into the