Python并删除列表列表中的重复项，而不管列表中的顺序如何 [英] Python and remove duplicates in list of lists regardless of order within lists

问题描述

我进行了搜索，但还没有找到与我相同的问题.我想从python中的列表列表中删除重复项；但是，我不在乎值在列表中的顺序.目前我这样做的方式太耗时了.

I have searched and haven't quite found the same question as mine. I want to remove duplicates from a list of lists in python; however, I don't care what order the values are in the list. They way I am doing it currently is too time-consuming.

我想做什么:

A = [[1,2,3] , [2,3,4] , [3,4,5] , [3,2,4]]

我想搜索A并删除所有重复项.这里的重复项将是[2,3,4]和[3,2,4].这样可以减少到:

I want to search through A and remove all duplicates. The duplicates here would be [2,3,4] and [3,2,4]. This would reduce down to:

smaller_A = [[1,2,3] , [2,3,4], [3,4,5]]

我目前的情况:

todelete = []
for i in range(len(A)):
    for j in range(i+1,len(A)):
        if set(A[i]) == set(A[j]):
           todelete.append(j)

todelete = sorted(set(todelete))

smaller_A= [A[i] for i in range(len(A)) if i not in todelete]

同样，这可行，但是当我的列表很大时，这非常耗时.有任何想法吗?谢谢！

Again, this works, but it is very time consuming when my lists are large. Any ideas? Thanks!

推荐答案

冻结集非常适合需要嵌套集的此类情况:

Frozensets are perfect for cases like this, when you need to nest sets:

>>> A = [[1,2,3], [2,3,4], [3,4,5], [3,2,4]]
>>> smaller_A = {frozenset(x) for x in A}
>>> smaller_A
{frozenset({1, 2, 3}), frozenset({2, 3, 4}), frozenset({3, 4, 5})}

要转换回列表，您可以执行以下操作:

To convert back to lists, you can do this:

>>> [list(x) for x in smaller_A]
[[1, 2, 3], [2, 3, 4], [3, 4, 5]]

这不会保留列表或列表中元素的顺序. (尽管在这里没有什么不同.)

This won't conserve the order of your lists or the elements inside them. (Although it didn't make a difference here.)

如果您确实需要保留订单，则可以遍历A，同时跟踪到目前为止看到的冻结集:

If you do need to preserve order, you can iterate over A while keeping track of frozensets seen so far:

>>> A = [[1,2,3], [2,3,4], [3,4,5], [3,2,4]]
>>> seen = set()
>>> smaller_A = []
>>> for x in A:
...     if frozenset(x) not in seen:
...         smaller_A.append(x)
...         seen.add(frozenset(x))
...
>>> smaller_A
[[1, 2, 3], [2, 3, 4], [3, 4, 5]]

(这不是经过优化的；理想情况下，您只需调用一次frozenset(x)并将结果存储在变量中.)

(This isn't optimized; ideally, you'd only call frozenset(x) once and store the result in a variable.)

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