How do I find out a struct is empty?
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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.
采纳的回答
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))
A = struct;
isempty(fieldnames(A))
2 个评论
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))
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))
A = rmfield(A,'B'); % non-empty struct array with no fields
is_empty_struct = isempty(A), has_no_fields = isempty(fieldnames(A))
A = A([]); % empty struct array with no fields
is_empty_struct = isempty(A), has_no_fields = isempty(fieldnames(A))
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