python中的列表列表集 [英] set of list of lists in python

问题描述

我有一个列表列表:

mat = [[1,2,3],[4,5,6],[1,2,3],[7,8,9],[4,5,6]]

并且我想转换为设置，即删除重复列表并从中创建一个新列表，其中仅包含唯一列表.

and I want to convert into a set i.e. remove the repeating lists and creating a new list out of it which will only contain the unique lists.

在上述情况下，所需答案将为

In above case the required answer will be

[[1,2,3],[4,5,6],[7,8,9]]

但是当我执行set(mat)时，它给了我错误

But when I do set(mat), it gives me error

TypeError:不可散列的类型:列表"

TypeError: unhashable type: 'list'

能请你解决我的问题吗?预先感谢！

Can you please solve my problem. Thanks in advance!

推荐答案

由于列表是可变的，因此不能进行散列.最好的选择是将它们转换为元组并形成一个集合，像这样

Since the lists are mutable, they cannot be hashed. The best bet is to convert them to a tuple and form a set, like this

>>> mat = [[1,2,3],[4,5,6],[1,2,3],[7,8,9],[4,5,6]]
>>> set(tuple(row) for row in mat)
set([(4, 5, 6), (7, 8, 9), (1, 2, 3)])

我们遍历mat，一次一次列出一个列表，将其转换为元组(这是不可变的，因此set很酷)，并且生成器被发送到set函数.

We iterate through the mat, one list at a time, convert that to a tuple (which is immutable, so sets are cool with them) and the generator is sent to the set function.

如果您希望将结果作为列表列表，则可以通过将set函数调用的结果转换为列表来将其扩展为这样的列表

If you want the result as list of lists, you can extend the same, by converting the result of set function call, to lists, like this

>>> [list(item) for item in set(tuple(row) for row in mat)]
[[4, 5, 6], [7, 8, 9], [1, 2, 3]]

这篇关于python中的列表列表集的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！