找到数值最接近的索引 [英] Find the index of numerically closest value

问题描述

  A = [1 4 6 9 11 13 15 18 21] 
 
 B = [2 10 19] 
  

是否有我可以使用的函数对于B中的每一个元素，我都可以找到A中最接近这个元素的索引。例如，在上面的例子中：2,10和19在数值上最接近于A中的1,9和18，而1，9和18的索引是1,4和8，所以函数应该返回[1 4 8]。

我知道我可以使用循环来做到这一点，但matlab并不真的喜欢循环加我的矩阵太大，迭代所有的值将是非常昂贵的时间。

解决方案

我会按以下步骤操作：

 ％clc，全部清除，全部关闭
 A = [1 4 6 9 11 13 15 18 21]; 
 B = [2 10 19]; 
 C = abs（bsxfun（@ minus，A'，B））; 
 [〜，idx] = min（C（：，1：size（C，2）））
  

Say I have 2 matrices in matlab :

A = [1 4 6 9 11 13 15 18 21]

B = [2 10 19]

Is there a function I can use so that, for every element in B, I am able to find the index of the closest value to that element in A. For instance, in the above example: 2,10 and 19 are numerically closest to 1,9 and 18 in A, and the indices of 1, 9 and 18 are 1,4 and 8, so the function should return [1 4 8].

I know I can use loops to do this but matlab doesn't really like loops plus my matrices are too big and iterating through all values would be very expensive on time.

解决方案

I would proceed as follows:

% clc,clear all,close all
A = [1 4 6 9 11 13 15 18 21];
B = [2 10 19];
C = abs(bsxfun(@minus,A',B));
[~,idx] = min(C(:,1:size(C,2)))

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