在MATLAB中获取置换的映射 [英] Getting the mapping for a permutation in MATLAB

问题描述

说我有两个数组，其中一个是另一个的排列:

Say I have two arrays where one is a permutation of the other:

A = [2 1 5 3 7]
B = [7 2 1 3 5]

在两个数组中都没有重复.

with no repetitions in either array.

如何获取两者之间的置换映射?

How can I obtain the permutation mapping between both?

例如A->B应为:

[2, 3, 5, 4, 1]

这意味着:

A(1) -> B(2)
A(2) -> B(3)
A(3) -> B(5)
A(4) -> B(4)
A(5) -> B(1)

更新:

是否有不使用ismember的 fast 矢量化解决方案?以我的经验，对于很大的数组，ismember往往很慢.

Update:

Is there a fast vectorized solution that does not use ismember ? In my experience, ismember tends to be slow for very large arrays.

推荐答案

这是怎么回事:

[i a] = sort(A);
[i b] = sort(B);
mapping = b(a)

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