"cycle for" between matrix with a variable in the name

Hi;

I have a series of matrix like A1, A2....AN and i want to perform an operation like

for i=1:N

B=B+A"i"(:,2)

end

how do i have to format the A"i"(:,2) part?

thank you

[Steven Lord]

Can you dynamically create variables with numbered names like A1, A2, A3, etc.? Yes.

Should you do this? The general consensus is no. That Discussions post explains why this is generally discouraged and offers several alternative approaches.

Answer 1

[Shivam]

Hi Andrea,

Refer to the example implementation:

N = 5; % Example no of matrix
A = {A1, A2, A3, A4, A5}; % Cell array containing matrices

% Initialize B
B = zeros(size(A{1}, 1), 1); % Assuming all matrices have the same number of rows

% Perform the operation
for i = 1:N
    B = B + A{i}(:, 2);
end

[Andrea]

Thank you for your answer, but i realized my problem is a little more complicated because I am working with struct of the type B.C1, B.C2....B.C100. So my code line is

for i=1:100

A=A+B.(C{i})(:,12);

end

i tried with and without (), but i had the error: Undefined variable 'C'.

Do you know how can I solve this too? I searched on this site but didn't find a solution.

[Voss]

A = zeros(size(B.C1,1),1);
for ii = 1:100
     A = A + B.("C"+ii)(:,12); 
end

https://www.mathworks.com/help/matlab/matlab_prog/generate-field-names-from-variables.html

[Stephen23]

"...I am working with struct of the type B.C1, B.C2....B.C100"

Rather than forcing pseudo-indices into the fieldnames it would be simpler and more efficient to use actual indexing.