使用Python和Sympy以可预测的顺序生成唯一的排列

Question

I have a list of elements in python. In the final code, the length of the list will be variable and the elements of my list much more lengthy, but I can demonstrate my question with three dummy elements.

Basically, for any list of length n, there will be n-1 identical elements, and 1 unique element.

So, in the example of three elements I have:

test = ['b', 'a', 'a']

For small cases such as 3, where I can verify by eye the order of the elements, I have been using a function from the Sympy module, as below:

permutations = list(multiset_permutations(test))

However, once cases become too large, I'm not certain that the order will be predictable. And, checking the official documentations doesn't really clarify the issue for me very well.

Is there a way to generate these permutations in a predictable order such that I could know, for example:

permutations[0] = ['b', 'a', 'a']
permutations[1] = ['a', 'b', 'a']
permutations[2] = ['a', 'a', 'b']

Thank you for any help that can be given.

Answer 1

The elements are ordered before the permutations are generated by multiset_permutations . Your result will not depend on the order of the input items.