find length of a field within structure and specific values

Question

Nicolas 2017-1-26

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/322062-find-length-of-a-field-within-structure-and-specific-values

回答： George Abrahams 2022-12-30

Hello,

I create a structure using the script below. I would like to know how can I find the length of each field and how can I find specific values within them?

Thank you very much

for ii = 1 : length(SplitDom); 
       Name_DomCoord = strcat('DomCoord',num2str(ii));
       variable.(Name_DomCoord) = model.geom(Name_Geom).obj(SplitDom(ii)).getVertexCoord();   
end

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Answer 1

Sruthi Geetha 2017-1-30

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https://ww2.mathworks.cn/matlabcentral/answers/322062-find-length-of-a-field-within-structure-and-specific-values#answer_252588

在 MATLAB Online 中打开

"getfield" function can be used to get the value of each field in the array. Refer the following link to know how to use the "getfield" function:

https://www.mathworks.com/help/matlab/ref/getfield.html

The length of each field in the array can be found by using "structfun" in combination with "numel" function.

For example:

 clear s; % save old stuff!
     s.a=1:10;
     s.b=pi;
     s.c=magic(3);
     r=structfun(@numel,s)
%{
% r =
     10
      1
      9
%}

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Nicolas 2017-1-30

thank you

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Answer 2

George Abrahams 2022-12-30

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https://ww2.mathworks.cn/matlabcentral/answers/322062-find-length-of-a-field-within-structure-and-specific-values#answer_1138277

在 MATLAB Online 中打开

The problem with the structfun approach is that the array output relates to the structure's field order. If you don't want to rely on a particular field order and/or want to keep the field names for readability, you could use my fieldfun function on File Exchange / GitHub. It's like structfun, but it outputs a structure with the same fields as the input structure.

variable = struct( 'DomCoord1', 1, 'DomCoord2', [2 3], ...
    'DomCoord3', [4 5 6] );
fieldfun( @numel, variable )
% ans = struct with fields:
%     DomCoord1: 1
%     DomCoord2: 2
%     DomCoord3: 3