Adding dissimilar structures together (not overwriting similar field values)

Hello!

I have a series of simulation results that I want to put together into 1 structure.

S=load('results1.mat')
S(2)=load('results2.mat')
and so on.

This works well, except for when the fieldnames are not completely the same.

Lets say that results1.mat contains 280 field names, results2.mat contains 283 field names, and that 279 fieldnames are completely the same.

I would like to have all the fieldnames in my structure S. If the separate results-file didn't contain the fieldname, I want the fieldvalue to be empty. And unlike examples elsewhere on the internet, in my case I do not want to overwrite fields, rather I want to have columns with fieldvalues for each simulation run.

How can I do this in an automated way?

Thank you very much in advance!

[Amy]

I think I solved my problem:

function A=merge_dissimilar_struct(A,B)
a=fieldnames(A);
b=fieldnames(B);

      if ~isequal(a,b);
          %Adding struct B to struct A, dissimilar fieldnames.
          %Create a cell of fieldnames that do not occur in A, but do occur in B.

          %Add fieldnames b of struct B (empty) to struct A.
          for xx=1:length(b)
              if ~isfield(A,char(b(xx)))
                  A().(char(b(xx)))=[];
              end
          end

          %Add fieldnames a of struct A (empty) to struct B.
          for xx=1:length(a)
              if ~isfield(B,char(a(xx)))
                  B().(char(a(xx)))=[];
              end
          end
      end

      B=orderfields(B,A);
      n=size(A,2);
      A(n+1)=B;
  end

[Jan]

Note: a{xx} is smarter than char(a(xx)).

Answer 1

[Jan]

Or simpler:

function A = AppendStruct(A, B)
fB = fieldnames(B);
nA = numel(A) + 1;
for ifB = 1:numel(fB)
  field = fB{ifB};   % [EDITED, typo, () -> {}]
  A(nA).(field) = B.(field);
end

Now the existing fields are reused and new fields are created automatically.

[Amy]

With your code I get an error:

C.A=ones(2,2);
C.B=ones(15,2);

D.A=zeros(2,5);
D.B=zeros(15,5);

EE=AppendStruct(C,D);

Argument to dynamic structure reference must evaluate to a valid field name.

Error in AppendStruct (line 6) A(nA).(field) = B.(field);

[Jan]

@Amy: This was a typo. See [EDITED].

Answer 2

[Guillaume]

Another variant of the function:

function A = merge_dissimilar_struct(A,B)
   for fld = setdiff(fieldnames(A), fieldnames(B))'
      A(end).(fld{1}) = [];   %add mising fields to A
   end
   for fld = setdiff(fieldnames(B), fieldnames(A))'
      B(end).(fld[1}) = [];   %add mising fields to B
   end
   A = [A, B];
end