Can you set struct to always display dimensions instead of field values?

In prior Releases, the default command line display for a structure was to show the array size. Here state is a struct with three fields.

>> state

ans = 

  struct with fields:

          mission_number: [1x13549 double]
       software_revision: [1x13549 double]
     vehicle_temperature: [1x13549 double]
     

In the latest release, the values of the arrays are shown instead.

>> state

ans = 

  struct with fields:

          mission_number: [0 0 0 0 0 ... ]
       software_revision: [22 22 22 ... ]
     vehicle_temperature: [28.9411 ... ]
 

I want a quick way to look at the sizes of my structs and the arrays within those structs. I don't use the MATLAB GUI, do please don't tell me to look in the workspace Variables panel... You can force the old (more useful!) method if the window is very narrow.

Is there a way to force the struct output to only use the old method?

[Walter Roberson]

In prior Releases, the default command line display for a structure was to show the array size.

Not completely true. When the field only had a small number of elements, the contents were shown. If I recall correctly, 4 elements was the usual limit.

Answer 1

[bubbleguy]

I just updated Matlab to 2022a and I found the new feature that Nick Nidzieko described is very annoying. For most of people, knowing the dimension of a struct field is much more important and valuable than knowing a few values of the field. I hope Matlab can reverse back this feature.

Answer 2

[Voss]

I don't know if there's a setting to control that, but you can always write your own function to do it.

Here's one you might try out, which will display the size and class of each field of a scalar struct:

s = struct( ...
    'mission_number',randn(1,13549), ... % using fields of various sizes here
    'software_revision',randn(1,149), ...
    'vehicle_temperature',randn(1,3549));
struct_disp(s);

         mission_number: [1x13549 double]
      software_revision: [1x149 double]
    vehicle_temperature: [1x3549 double]

s.new_cell_field = repmat({[1 2 3]},100,42,13); % include a 3D cell array in s
struct_disp(s);

         mission_number: [1x13549 double]
      software_revision: [1x149 double]
    vehicle_temperature: [1x3549 double]
         new_cell_field: [100x42x13 cell]

function struct_disp(s)
f = fieldnames(s);
nf = max(cellfun(@numel,f))+4;
fprintf_format = sprintf('%%%ds: [%%s %%s]\n',nf);
for ii = 1:numel(f)
    size_str = sprintf('%dx',size(s.(f{ii})));
    size_str(end) = [];
    fprintf(1,fprintf_format,f{ii},size_str,class(s.(f{ii})));
end
end

Answer 3

[Walter Roberson]

If you were willing to wrap the struct within a class, then you could customize the display format; see https://www.mathworks.com/help/matlab/matlab_oop/custom-display-interface.html

Wrapping within a class is not always convenient, so the idea of creating your own display function may make more sense, as shown in https://www.mathworks.com/matlabcentral/answers/1670244-can-you-set-struct-to-always-display-dimensions-instead-of-field-values#answer_916144