How do I find out a struct is empty?

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Sean
Sean 2023년 9월 27일
편집: Sean 2023년 9월 28일
There are instances in a .mat file where there is information and no information within a particular struct. I'm trying to figure out how to identify that within the struct where there is no furture information avaliable, it's an empty struct.
Let's say a .mat file contains below
A = struct;
A.B = '1';
A.C = '2';
A.D = '3';
but there is another file that contains only what's below
A = struct;
Depending on what which file, or mutiple files that contain various numbers of variables, how do I check if a struct is empty so that I'll be able to initialize the data that is not empty into EditFields of an application.

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Voss
Voss 2023년 9월 27일
It looks like you want to find out whether a struct has any fields or not, for which you can use isempty(fieldnames(A))
A = struct;
A.B = '1';
A.C = '2';
A.D = '3';
isempty(fieldnames(A))
ans = logical
0
A = struct;
isempty(fieldnames(A))
ans = logical
1
  댓글 수: 2
Voss
Voss 2023년 9월 27일
편집: Voss 2023년 9월 27일
Whether the struct is empty is another question, as empty and non-empty struct arrays can have fields or no fields.
A = struct('B',{}); % empty struct array with one field ('B')
is_empty_struct = isempty(A), has_no_fields = isempty(fieldnames(A))
is_empty_struct = logical
1
has_no_fields = logical
0
A = struct('B',{1 2 3}); % non-empty (size 1-by-3) struct array with one field ('B')
is_empty_struct = isempty(A), has_no_fields = isempty(fieldnames(A))
is_empty_struct = logical
0
has_no_fields = logical
0
A = rmfield(A,'B'); % non-empty struct array with no fields
is_empty_struct = isempty(A), has_no_fields = isempty(fieldnames(A))
is_empty_struct = logical
0
has_no_fields = logical
1
A = A([]); % empty struct array with no fields
is_empty_struct = isempty(A), has_no_fields = isempty(fieldnames(A))
is_empty_struct = logical
1
has_no_fields = logical
1
Sean
Sean 2023년 9월 28일
편집: Sean 2023년 9월 28일
Thank you for helping me out, I tried to implement it, but I implemented a try catch statement and works.

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