How do I find out a struct is empty?

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.

 Risposta accettata

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

2 Commenti

Voss
Voss il 27 Set 2023
Modificato: Voss il 27 Set 2023
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 il 28 Set 2023
Modificato: Sean il 28 Set 2023
Thank you for helping me out, I tried to implement it, but I implemented a try catch statement and works.

Accedi per commentare.

Più risposte (0)

Prodotti

Release

R2018b

Richiesto:

il 27 Set 2023

Modificato:

il 28 Set 2023

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by