Question

listA = ["A","B","C","D"]

由此，我只想要以下输出：

["A","B","C"]
["B","C","D"]
["C","D","A"]
["D","A","B"]

我已经在这里查看了关于排列的各种问题，但到目前为止我无法做到这一点。任何帮助将不胜感激。

Answer 1

另一种方法 - 蛮力，

def permutation(L):
    for i in range(len(L)):
        x = L[i:i+3]
        length = len(x)
        if length != 3:
            x = x + L[:3-length]
        print(x)


L = ["A","B","C","D"]
permutation(L)

Answer 2

您可以使用itertools.cycle和itertools.islice。

要获取您显示的订单（建议@tobias_k）：

>>> from itertools import cycle, islice
>>> listA = ["A","B","C","D"]
>>> [list(islice(cycle(listA), i, i+3)) for i in range(len(listA))]
[['A', 'B', 'C'], ['B', 'C', 'D'], ['C', 'D', 'A'], ['D', 'A', 'B']]

要获得另一种顺序排序：

>>> it = cycle(listA)
>>> [list(islice(it,3)) for _ in range(len(listA))]
[['A', 'B', 'C'], ['D', 'A', 'B'], ['C', 'D', 'A'], ['B', 'C', 'D']]

Answer 3

感谢您的所有答案。我收到了一位朋友的回答，我想在这里分享一下。它是这样的。

listA = ["A","B","C","D"]
listB = listA + [listA[0]] + [listA[1]]

catch = []
for i in range(len(listA)):
    A = listB[i]
    B = listB[i+1]
    C = listB[i+2]
    catch.append([A,B,C])
print catch

Python排列依次排列

3 个答案: