How do I make a script to show the field names of struct in a struct

I currently have the code below to list out only the structs.

sTable=struct2table(s);

sStruct=sTable(:,vartype('struct'));

Inside the table there are 3 1x1 structs that I wanted to access.

I can get there via clicking on the variables workspace or using individual fieldnames

a=fieldnames(sStruct.v1_abc)

but I wanted to have a script to automatically access it by entering the first colnmn names show the fields.

Thanks in advance.

[Matt J]

Please attach sStruct and also clarify "by entering the first colnmn names show the fields".

[Emily]

a1='abcd';

a2=[1 2 3];

s.a=char(a1,a2);

s.b.a = ones(3);

s.b.b = eye(4);

s.c.c = magic(5);

s.d=char(a2,a1);

For example, for the s Struct above I want it to show the fieldnames for s.b and s.c without going to the variables workspace.

Answer 1

[Matt J]

Something like this?

a1='abcd';
a2=[1 2 3]; 
s.a=char(a1,a2);
s.b.a = ones(3);
s.b.b = eye(4);
s.c.c = magic(5);
s.d=char(a2,a1);

showsubfields(s,'b','c')

Field: b
   a
   b
Field: c
   c

function showsubfields(S,varargin)

   for i=1:numel(varargin)
       
     fn=varargin{i};
     if ~isstruct(S.(fn)); continue; end
     
     disp("Field: "+fn)
     
     subfns=fieldnames(S.(fn));
     
     disp(char("   "+subfns))
     
   end
end

[Emily]

Thanks for commenting!

I tried it out but it didn't work for my example.

For clarification I have a lot more data and don't know which datas are structs or not until I go into the variable workspace for s. So I wanted to find a way to automate it instead of me going into find every single structs.

I've also tried to convert it to a table. But still not sure how to have matlab read the function and have it display out the struct with fields for all the structs in s.

sTable=struct2table(s,"AsArray",true);
sStruct=sTable(:,vartype('struct'));

I want the output to be s.b and s.c with the field names

s.b
a
b

s.c
c

[Matt J]

I want the output to be s.b and s.c with the field names

As you can see above, that is the output that my code gives for the example you've provided. If it is failing on more general input, you should attach those examples in a .mat file.

[Emily]

For clarification I have a lot more data and don't know which datas are structs or not until I go into the variable workspace for s. So I wanted to find a way to automate it instead of me going into find every single structs.

I tried adding more data. Out of here I would like to display only the struct and the field names inside of those structs without having to input which ones are structs.

a1='abcd';
a2=[1 2 3]; 
s.a=char(a1,a2);
s.b.a = ones(3);
s.b.b = eye(4);
s.c.c = magic(5);
s.d = char(a2,a1);
s.e = magic(2);
s.f = char(a1,a2);
s.g = s.b;

For the showsubfields(s,'b'), I have to know which ones are structs or not. I just want to input showsubfields(s) and have it print all the structs with the fieldnames inside those structs.

[Matt J]

a1='abcd';
a2=[1 2 3]; 
s.a=char(a1,a2);
s.b.a = ones(3);
s.b.b = eye(4);
s.c.c = magic(5);
s.d = char(a2,a1);
s.e = magic(2);
s.f = char(a1,a2);
s.g = s.b;

showsubfields(s)

Field: b
   a
   b
Field: c
   c
Field: g
   a
   b

function showsubfields(S)

     Fields=fieldnames(S);

     for i=1:numel(Fields)
     fn=Fields{i};
     if ~isstruct(S.(fn)); continue; end
     
     disp("Field: "+fn)
     
     subfns=fieldnames(S.(fn));
     
     disp(char("   "+subfns))

     end
     

end

[Emily]

That's perfect! Thank you so much!

[Matt J]

You're welcome, bu please Accept-click to indicate that it worked.