用其他值替换矩阵中的值 [英] Replace values in matrix with other values

问题描述

我有一个带有整数的矩阵，我需要将所有2的出现都替换为-5.最有效的方法是什么?我是按照下面的方法做的，但是我敢肯定还有更优雅的方法.

I have a matrix with integers and I need to replace all appearances of 2 with -5. What is the most efficient way to do it? I made it the way below, but I am sure there is more elegant way.

a=[1,2,3;1,3,5;2,2,2]
ind_plain = find(a == 2)
[row_indx col_indx] = ind2sub(size(a), ind_plain)
for el_id=1:length(row_indx)
    a(row_indx(el_id),col_indx(el_id)) = -5;
end

我不是循环，而是寻找类似的东西:a(row_indx，col_indx)= -5，这不起作用.

Instead of loop I I seek for something like: a(row_indx,col_indx) = -5, which does not work.

推荐答案

find. 改用逻辑索引:

a(a == 2) = -5

如果要搜索矩阵是否等于inf，则应使用

In case of searching whether a matrix is equal to inf you should use

a(isinf(a)) = -5

一般情况是:

Mat(boolMask) = val

其中Mat是您的矩阵，boolMask是另一个logical值矩阵，而val是分配值

where Mat is your matrix, boolMask is another matrix of logical values, and val is the assignment value

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