how to index a cell array

Question

li yan 2018-5-23

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/402091-how-to-index-a-cell-array

评论： li yan 2018-5-23

Hi, I encountered a Matlab problem again. I want to access all struct field elements, which is an element of a cell array, at one time, not using loop. Such as:

s{1} = struct('ID',1,'other field',...);
s{2} = struct('ID',2,'other field',...);

I want to access all ID values in the cell s, I write the code like this:

IDs = [s{:}.ID];

This does not work, how to access all ID values not using for loop, please?

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Stephen23 2018-5-23

在 MATLAB Online 中打开

If you used just one non-scalar structure (rather than lots of scalar structure in a cell array) then the solution would be very simple:

S(1) = struct('ID',1,'other field',...);
S(2) = struct('ID',2,'other field',...);
[S.ID]

Simpler, more efficient code through better data design. Why make your code more complex than this?

li yan 2018-5-23

Thank for you answer.

I'm doing information fusion with matlab, the track numbers vary dynamic, a cell struct is convenient to store track information.

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Answer 1

Ameer Hamza 2018-5-23

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/402091-how-to-index-a-cell-array#answer_321516

在 MATLAB Online 中打开

You can do this in Two steps

temp = [s{:}];
allIDValues = [temp.ID];

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Stephen23 2018-5-23

Note that in Ameer Hamza's answer the first line of code converts your cell array of scalar structures into one non-scalar structure. If you had stored your data in a non-scalar structure in the first place, then you would not need this extra step.

li yan 2018-5-23