检查元组内的负重复项

Question

我是 python 的新手，我编写了这段极度未优化的代码，用于返回从 -(number) 到 (number) 的所有排列，不包括零。问题是，结果包含我不想要的条目，例如 (-2,2)。返回的元组不应包含相同的正数和负数。下面的代码通过将两个值相加并检查它是否等于零来工作，但是当输入数字（num 值）大于 2 时它会变得复杂。而且，您可能会说代码极度未优化（需要大约 10 分钟num=6) 我怎样才能让它更优化？谢谢！

from itertools import permutations
num = 2
result = []
l = []
stuff = [i for i in range(-num,num+1)]
for i in range(0, len(stuff)+1):
        for subset in permutations(stuff, i):
            if 0 not in subset:
                if len(subset)==num:
                    if sum(subset[:]) != 0:
                        with open('geneorder.txt','a') as txt_file:
                            txt_file.write('\n'+str(subset).replace('(','').replace(')','').replace(', ',' '))
                        result.append(subset)
print(result)
print(len(result))

Answer 1

一个比较有效的解决方案是简单地从 1 到 n 的数字列表开始，然后生成 positive/negative 项的所有组合，然后排列每个组合。

from itertools import permutations
def generate_positive_negatives(num):
    def collect(curr, idx, results):
        if idx == len(curr):
            results.append(curr.copy())
            return

        collect(curr, idx + 1, results)
        # toggle, recurse, backtrack
        curr[idx] *= -1
        collect(curr, idx + 1, results)
        curr[idx] *= -1
        results

    results = []
    curr = list(range(1, num + 1))
    collect(curr, 0, results)
    return list(tuple(choice) for combo in results for choice in permutations(combo))

for perm in generate_positive_negatives(2):
    print(perm)

输出

(1, 2)
(2, 1)
(1, -2)
(-2, 1)
(-1, 2)
(2, -1)
(-1, -2)
(-2, -1)

检查元组内的负重复项

Check negative duplicates inside a tuple

python

optimization

tuples

list

permutation