逻辑索引而不是查找 [英] logical indexing instead of find

问题描述

我想改善一段代码

LaserS_P=rand(20,3); % duumy data
LaserS_P(1:4:end,1)=0;
index_= find( LaserS_P(:,1)); % finds o element in first row of 20*3 matrix.
LaserS_P_new=LaserS_P(index_,:); % remove all rows (index_) from matrix

在这种情况下，如何使用逻辑索引.

How can i use logical indexing for this case.

推荐答案

要删除所有零值行(这不是您的示例所做的工作)，可以按如下所示使用逻辑索引:

To remove all the zero-valued rows (which is not what your example does), you can use logical indexing as follows:

LaserS_P=rand(20,3); % dummy data
LaserS_P(1:4:end,1)=0;
index_= ( LaserS_P(:,1) == 0); %# finds 0 element in first col of 20*3 matrix.
%# index_ is a logical vector with ones wherever LaserS_P's first col is 0
LaserS_P_new=LaserS_P(~index_,:); %# remove all rows (index_) from matrix

%# alternatively
LaserS_P_new(index_,:) = []; %# remove all rows (index_) from matrix

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