I have data in 3D array and I know indices in the first two dimensions. How do I collect all data without for loop?

Question

Nina Laorodphun 2023-5-18

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1967249-i-have-data-in-3d-array-and-i-know-indices-in-the-first-two-dimensions-how-do-i-collect-all-data-wi

编辑： Matt J 2023-5-18

For example

Data(:,:,1) = [1,2,3

4,5,6

7,8,9];

Data(:,:,2) = [11,22,33

44,55,66

77,88,99];

I expect the output to be output(:,:,1) = [1,3

7,5]

output(:,:,2) = [11,33

77,55]

I know that the index are idxRow = [1,1

3,2];

idxCol = [1,3

1,2];

How do I use idxRow and idxCol to extract everything from Data?

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Answer 1

Matt J 2023-5-18

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1967249-i-have-data-in-3d-array-and-i-know-indices-in-the-first-two-dimensions-how-do-i-collect-all-data-wi#answer_1238984

编辑：Matt J 2023-5-18

在 MATLAB Online 中打开

One way

Data(:,:,1) = [1,2,3
    4,5,6
    7,8,9];
Data(:,:,2) = [11,22,33
    44,55,66
    77,88,99];
idxRow = [1,1
    3,2];
idxCol = [1,3
    1,2];
[m,n,p]=size(Data);
idx=sub2ind([m,n],idxRow,idxCol);
D=reshape(Data,[],p);
output = reshape(D(idx,:),[size(idxRow),p])
output = 
output(:,:,1) =

     1     3
     7     5


output(:,:,2) =

    11    33
    77    55