How to generate all combinations of a vector

Question

Vishal Sharma 2018-3-23

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/390317-how-to-generate-all-combinations-of-a-vector

评论： John D'Errico 2018-3-23

I want to generate all possible combinations of a vector A=[1 2 3] to get answer [1 1 1; 1 1 2; 1 1 3; 1 2 1; 1 2 2; 1 2 3]

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

John D'Errico 2018-3-23

You have listed [1 1 1] in the list of "combinations". That would seem to imply that replicates are allowed, since 1 appears only once in A. So, why not [2 2 2] in that set? Why not [3 3 3]? Why not [1 3 3]?

Most of the set you generated are sorted. But you list both [1 1 2], and [1 2 1]. So why not [2 1 1]? Why not [3 2 1]?

If you want a serious answer, you need to explain what you need. Or perhaps give a far better example.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

David Fletcher 2018-3-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/390317-how-to-generate-all-combinations-of-a-vector#answer_311628

在 MATLAB Online 中打开

Generally, perms gives the permutations of a vector eg.

 >> perms([1 2 3])
ans =
       3     2     1
       3     1     2
       2     3     1
       2     1     3
       1     3     2
       1     2     3

However, I'm not sure that's what you are asking since you've included [1 1 1] as a possible combination of [1 2 3] - I have no idea how [1 1 1] is a combination of [1 2 3] (though by extension of that logic, I'm not sure why you don't include [2 2 2] and [3 3 3] in your list, as well as numerous other things if you're going to repeat elements)