问题描述
我有两个尺寸相似的数据矩阵A和B.我打算将的每个元素除以B的相应元素.为此，matlab提供了一个快捷方式，如C = A./B.但是，B有许多零元素，对于这些元素，我希望C的元素为零而不是NAN. MATLAB是否提供有效的方式来做到这一点?我可以循环执行此操作，但这将非常昂贵.谢谢.
I have two data matrices A and B of similar dimensions. I intend to divide each element of A by its corresponding elements of B. For this matlab provides a shortcut as C = A./B. However, B has many zero elements , for such elements I want elements of C to be zero rather than NAN . Does MATLAB provide a way to do this in an efficent manner? I could do this in a loop but that would be very expensive.Thanks.
推荐答案
是.您可以使用逻辑索引:
Yes. You can use logical indexing:
C = zeros(size(A));
t = logical(B);
C(t) = A(t)./B(t);
使用逻辑索引时，将仅评估与t的true元素相对应的A，B和C元素. t是true，仅当B不为零时.请注意，C被预先初始化为零，以自动处理由于B为零而未被评估的情况.
With logical indexing, only the elements of A, B and C corresponding to true elements of t will be evaluated. t is true only where B is non-zero. Note that C is pre-initialized to zeros to automatically take care of the cases that are not evaluated because B is zero.
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