How can I change all fields in a structure except one?

Hi!

I've got a structure with 17 fields and 68 values for each of them (so a 1x68 struct with 17 fields). Since some of the 68 values don't have information, I would like to fill them by copying the information of another value (which has information) which I can do simply like this:

mystruct(67) = mystruct(65);

But this copies all the fields of the 65th value of the structure into the fields of the 67th value of the structure, and I would like to keep the first field of the 67th value of the structure intact (because it's the name field). Any idea how I can do this?

Thanks very much in advance.

Answer 1

[Dave B]

You could iterate over the fields and copy them each one at a time unless they were the field you wanted to preserve, but I wouldn't recommend that for this case. Instead, how about just storing the name temporarily and setting it back again after?

cachename = mystruct(67).name; % or whatever it's called
mystruct(67) = mystruct(65);
mystruct(67).name = cachename;

You could even put that into a little function if you liked:

function s=copyallbutname(s,from,to)
    n=s.name;
    s(to)=s(from);
    s(to).name=n;
end

If you want to iterate over names, you can do it like this:

fn = fieldnames(mystruct)

% Note I'm starting with 2 because you said you don't want the first field
% but I'd recommend using names not order if it's a struct!
for i = 2:numel(fn) 
    % can check fn{i}=="somename"
    % or ismember(fn{i},listoffieldstokeep)
    % etc.
    
    % To use fn{i}:
    mystruct(67).(fn{i}) = mystruct(65).(fn{i});
end

[Guillem Campins]

Ah, of course I could just save it first, I didn't think of that hahaha

Thanks so much mate