Convert a cell with structures into a matrix

Question

Alejandro Fernández 2021-1-30

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/731328-convert-a-cell-with-structures-into-a-matrix

编辑： Stephen23 2021-1-30

Hi, does anyone know how to could I go from the information I have stored in the variable A to what I have in the variable matrix?

% Input data.
A = cell(3,1);
A{1}.data = [1 2 3];
A{1}.a = 0;
A{2}.data = [4 5 6];
A{2}.a = 1;
A{3}.data = [7 8 9];
A{3}.a = 3;
% Result to obtain.
matrix = [1 2 3; 4 5 6; 7 8 9];

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Answer 1

David Hill 2021-1-30

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https://ww2.mathworks.cn/matlabcentral/answers/731328-convert-a-cell-with-structures-into-a-matrix#answer_610278

在 MATLAB Online 中打开

m=[];
for k=1:3
    m=[m;A{k}.data];
end

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Stephen23 2021-1-30

@David Hill: you forgot this:

https://www.mathworks.com/help/matlab/matlab_prog/preallocating-arrays.html

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Answer 2

Stephen23 2021-1-30

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/731328-convert-a-cell-with-structures-into-a-matrix#answer_610298

编辑：Stephen23 2021-1-30

在 MATLAB Online 中打开

Rather than inefficiently storing lots of scalar structures in a cell array, you should just use one efficient non-scalar array, then your task is trivial:

S(1).data = [1 2 3];
S(1).a = 0;
S(2).data = [4 5 6];
S(2).a = 1;
S(3).data = [7 8 9];
S(3).a = 3;
M = vertcat(S.data) % this is all you need!
M = 3×3
     1     2     3
     4     5     6
     7     8     9