Extract fields from structure

Hello,

I have a structure A that includes 2 structures, B and C. I want to extract from structure "C" , to the workspace, specific fields that start with certain set of letter, i.e I want to extract fields that start wih XX_YY.

I did

S=[A.C(:)]; save('param.mat','-struct','S');

But the file takes forever to load to the workspace.

Thanks in Advance!

[Dyuman Joshi]

Is it necessary to save the file? (Might be for any computation after the extraction, I presume)

[Samy Alkhayat]

I actually not sure how to extract directly to workspace without saving to a variable and loading it.

[Dyuman Joshi]

It is, as the answers below show

Answer 1

[Stephen23]

A.C.XX_YY1 = 5;
A.C.XX_YY2 = 10;
A.C.ZZ = 3;
B = A.C;
F = fieldnames(B);
X = startsWith(F,'XX_YY');
B = rmfield(B,F(~X))

B = struct with fields:
    XX_YY1: 5
    XX_YY2: 10

[Samy Alkhayat]

Works! Thank you!

@Stephen23 any way to put the fields inside "B" into the workspace directly?

[Stephen23]

"any way to put the fields inside "B" into the workspace directly?"

https://www.mathworks.com/matlabcentral/fileexchange/26216-structure-fields-to-variables

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Answer 2

[Matt J]

S.C.XX_YY1=5;
S.C.XX_YY2=10;
S.C.ZZ=3;

f=fieldnames(S.C);

I=startsWith(f,'XX_YY');

f=string(f(I));

for fI=string(f(I))'
    
    Extraction.(fI)=S.C.(fI);
    
end

Extraction

Extraction = struct with fields:
    XX_YY1: 5
    XX_YY2: 10

[Samy Alkhayat]

@Matt J it works except I get the error below:

The logical indices contain a true value outside of the array bounds.

Any advice?

Thanks in advance!