Matlab中find()函数的逆函数是什么 [英] What is the inverse of find() function in matlab

问题描述

在Matlab中，我可以在矢量中找到所有非零条目，如下所示:

In Matlab I can find all non zero entries in a vector like this:

>> v = [0 1 0 0 1]

v =

     0     1     0     0     1

>> indices = find(v)

indices =

     2     5

假设我的向量v只能具有0和1值，从indices向量再现v的简单方法是什么?

Assuming that my vector v can only have 0 and 1 values, what is a simple way to reproduce v from the indices vector?

推荐答案

您必须知道v的形状(即，如示例中的v是多长的形状)，但是一旦知道这很简单:

you have to know what the shape v is (i.e. how long v is if it's a vector as in your example), but once you know that it's trivial:

n = 5;
v_reconstructed = zeros(1, n);
v_reconstructed(indices) = 1;

如果您不知道v多长时间，则不会捕获v中最后一个1之后的任何0 ...

if you don't know how long v is then you won't capture any 0s after the last 1 in v...

顺便说一句，如果您正在使用稀疏矩阵，那么您可能实际上希望这样做:

BTW if you are working with sparse matrices then you might want this actually:

v = sparse([0 1 0 0 1]);
v_reconstructed = full(v);

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