array subscripting

Question

AP 2011-6-2

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/8670-array-subscripting

I have a struct variable defined as follows:

my_data(3) = struct('x',[],'y',[],'f',[])
for i=1:3
   my_data(i).x = [1 2 3]*i;
   my_data(i).y = [1 2 3]*i;
   my_data(i).f = [1 2 3;4 5 6;7 8 9]*i;
end

Actually f is a matrix (N×M) which holds the value of a function for each (x,y) and stores its value in different measures. x and y are vectors (N×1). Therefore, my_data(1).f(:,2) means the value of the function in the second measure for experiment#1. I am trying to assign f to another variable (like new_f) columnwise. In other words, I am trying to assign the first columns of all the experiments (from 1 to 3) to the first column of new_f and so on. The following assigns each column of f but can I modify it a little bit to assign all the columns to new_f:

column1=arrayfun(@(S) S(:).f(:,1), my_data,'UniformOutput', false);
column2=arrayfun(@(S) S(:).f(:,2), my_data,'UniformOutput', false);
column3=arrayfun(@(S) S(:).f(:,3), my_data,'UniformOutput', false);

how can I combine all the above assignments into one neat assignment?

Thank you very much for your quick reply.

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Answer 1

Walter Roberson 2011-6-2

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/8670-array-subscripting#answer_11939

在 MATLAB Online 中打开

T = vertcat(S.f);
T = mat2cell(T, size(T,1), ones(1,size(T,2)));
[column1, column2, column3] = deal(T{:});

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Walter Roberson 2011-6-2

I was following the code sample that showed assignment in to separate variables. If you want them all in one matrix then the first line is all you need.

AP 2011-6-2