Use string name as variable name for struct

I've got field names of a struct that are:

data.A__B__C
data.A__B__D

I want to make a new struct as such:

newData.A.B.C. = data.A__B__C
newData.A.B.D = data.A__B__D

I want to make new fields for my structs as follows:

names = fieldnames(data)
newNames = strrep(names,'__', '.')
for k = 1:length(names)
    newData.(newNames{k,1}) = (data.(names{k,1}));
end

but I can't use the strings as fields for a new struct. I have to type every new variable by hand, of which I have over 100.

Is there some way that I can use the "newNames" variable to define a new struct with proper fields, instead of just 1 field with underscores?

[KSSV]

Note that in the line:

newData.A.B.C.

A.B.C. is not a filed name, it is a structure again.

[Alan Khalik]

yes, I want to create new fields for a structure. In

data.A__B__C

there is only 1 field: A__B__C, but I want to add new fields: A.B.C. I need this for compatibility with another function that I want to use.

Answer 1

[Stephen23]

D.A__B__C = 0.5;
D.A__B__D = pi

D = struct with fields:
    A__B__C: 0.5000
    A__B__D: 3.1416

F = fieldnames(D);
C = regexp(F,'_+','split');
Z = struct();
for k = 1:numel(F)
    Z = setfield(Z,C{k}{:},D.(F{k}));
end
Z.A.B

ans = struct with fields:
    C: 0.5000
    D: 3.1416

KSSV's comment here is very important to understand, and explains why your approach does not work:

https://www.mathworks.com/matlabcentral/answers/1649420-use-string-name-as-variable-name-for-struct#comment_1984655

You incorrectly tried to create one long fieldname with dots in it. But in reality, you are trying to define nested structures, and each structure has its own fieldnames, they do not "share" one fieldname as you were attempting. The dots are not part of a fieldname.

[Alan Khalik]

Thanks a lot. I see what I was doing wrong!