Data structure to represent multiple equivalent keys in set in Python?

Question

Currently, I want to find the correct data structure to meet the following requirement.

There are multiple arrays with disordered element, for example,

[1, 2], [2, 1], [3, 2, 2], [2], [2, 1, 3], [2, 2, 3]

After processing those data, the result is,

[1, 2], [2, 2, 3], [2], [1, 2, 3]

With sorted element in each array and filter the duplicate arrays.

Here are my thoughts:

• Data structure Set(Arrays)? - Failed. It seems there is only one array in the build-in set

  set([])

• Data structure Array(Sets)? - Failed. However, there is no duplicate element in the build-in set. I want to know whether there is one data structure like multiset in C++ within Python?

Answer 1

Transform your list to tuple(thus can be a item of set), then back to list.

>>> [list(i) for i in set([tuple(sorted(i)) for i in a])]
[[1, 2], [2], [2, 2, 3], [1, 2, 3]]