Julia中向量的原位重排? [英] In-place rearrangement of vector in Julia?

问题描述

是否可以在给定索引列表的情况下重新排列向量中的值?

Is it possible to rearrange the values in a vector given a list of indices?

我有两个数组，我想基于arr1排序arr2，这两个数组都是预先分配的.

I have two arrays and I want to sort arr2 based on arr1 which are both preallocated.

indices = zeros(length(arr1))
sortperm!(indices, arr1)
arr2[indices] <-- this returns a copy

推荐答案

permute!是您的朋友.使用REPL提示符上的?permute!检查帮助.

permute! is your friend. Check the help with ?permute! on the REPL prompt.

具体地说，

permute!(arr2,indices)

应该在OP中就地置换arr2.但是，文档建议在较大的向量上创建一个新副本可能会更好.

should permute in-place arr2 in the OP. But, the docs suggest on large vectors it might be better to just create a new copy.

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