英文:
Filtered product of lists without repetitions
问题
I can help with that. Here's an improved implementation using itertools to find all combinations without repetitions of given lists efficiently:
import itertoolsdef combinations(*all_lists):unique_combinations = set()for combo in itertools.product(*all_lists):if len(combo) == len(set(combo)):unique_combinations.add(tuple(sorted(combo)))return list(unique_combinations)
这是一个使用itertools的改进实现，可以高效地找到给定列表的所有不重复组合。
英文:
I need an efficient solution to find all combinations without repetitions of a given lists. It has to work like this:
l1 = [1, 2, 3]l2 = [3, 4, 5]combinations(l1, l2) = [(2, 4), (3, 4), (1, 5), (1, 4), (2, 3), (2, 5), (1, 3), (3, 5)]
The important thing is that I could use it for an arbitrary number of lists and in a very efficient way (preferably using itertools).
My current implementation is way too slow:
import itertoolsdef combinations(*all_lists: tuple[list[int]]):lists_product = itertools.product(*all_lists)res = set()for x in lists_product:if len(set(x)) == len(all_lists):x = tuple(sorted(x))res.add(x)return list(res)
I would appreciate any help.
答案1
得分: 1
以下是已翻译的内容：
这里有一个稍微更快的解决方案：
def combinations_2(*all_lists: tuple[list[int]]):len_all_list = len(all_lists)lists_product = list(itertools.product(*all_lists))fset = set(map(frozenset, lists_product))list_filter = list(map(sorted, list(filter(lambda x: len(x) == len_all_list, fset))))res_2 = list(map(tuple, list_filter))return res_2
由于你的结果 res 来自一个无序数据结构 set()，所以我对两个输出进行了排序。
import randomvalues = [1, 2, 3, 4, 5, 6, 7, 8, 9, 15, 20, 25, 30]l1 = random.choices(values, k=100)l2 = random.choices(values, k=100)res = combinations(l1, l2)res_2 = combinations_2(l1, l2)res_temp = sorted(res, key=lambda x: (x[0], x[1]))res_2_temp = sorted(res_2, key=lambda x: (x[0], x[1]))print(res_temp == res_2_temp)
这给出了以下结果：
True
然后是运行时间：
%timeit combinations(l1, l2)
7.1 ms ± 437 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
%timeit combinations_2(l1, l2)
2.56 ms ± 109 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
英文:
Here is a solution which is a little faster :
def combinations_2(*all_lists: tuple[list[int]]):len_all_list = len(all_lists)lists_product = list(itertools.product(*all_lists))fset = set(map(frozenset,lists_product))list_filter = list(map(sorted, list(filter(lambda x: len(x) == len_all_list, fset))))res_2 = list(map(tuple, list_filter))return res_2
As your result res is from a set() which is an unordered data structure. So I sorted the two outputs for comparing.
import randomvalues = [1, 2, 3, 4, 5, 6, 7, 8, 9, 15, 20, 25, 30]l1 = random.choices(values,k=100)l2 = random.choices(values,k=100)res = combinations(l1, l2)res_2 = combinations_2(l1, l2)res_temp = sorted(res, key=lambda x: (x[0], x[1]))res_2_temp = sorted(res_2, key=lambda x: (x[0], x[1]))print(res_temp == res_2_temp)
Which gives the result
> True
Then the running time :
%timeit combinations(l1, l2)
> 7.1 ms ± 437 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
%timeit combinations_2(l1, l2)
> 2.56 ms ± 109 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
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