Is it possible to check for existence of fields in nested structures with isfield in MATLAB 8.1 (R2013a)?

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MathWorks Support Team 2013-10-25

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https://ww2.mathworks.cn/matlabcentral/answers/103924-is-it-possible-to-check-for-existence-of-fields-in-nested-structures-with-isfield-in-matlab-8-1-r20

回答： Steven Lord 2022-12-16

采纳的回答： MathWorks Support Team

I have the following structure

a.b.c = 1;

I know it is possible to search for the nested

isfield(a.b,'c')

But I would like to check for the existence of the field 'c' even when I am not sure that the field 'b' exists, e.g.

isfield(a,'b.c');

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Answer 1

MathWorks Support Team 2013-10-25

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https://ww2.mathworks.cn/matlabcentral/answers/103924-is-it-possible-to-check-for-existence-of-fields-in-nested-structures-with-isfield-in-matlab-8-1-r20#answer_113264

There is no MATLAB function to determine the existence of fields in nested structures. The only workaround is to check separately for the existence of 'b' and of 'c':

isfield(a, 'b') && isfield(a.b, 'c')

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Answer 2

Steven Lord 2022-12-16

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https://ww2.mathworks.cn/matlabcentral/answers/103924-is-it-possible-to-check-for-existence-of-fields-in-nested-structures-with-isfield-in-matlab-8-1-r20#answer_1129637

在 MATLAB Online 中打开

Another approach that uses neither eval nor repeated calls to isfield is to use getfield.

a.b.c = 1;
isNestedField(a, 'b.c')
ans = logical
   1
isNestedField(a, 'b.d')
ans = logical
   0
isNestedField(1:10, 'a')
ans = logical
   0
function tf = isNestedField(s, thefields)
fieldlist = split(thefields, '.');
try
    getfield(s, fieldlist{:});
    tf = true;
catch
    tf = false;
end
end