How could I possibly iterate over three 3D arrays and use their variable names iteratively in the title and axes?

x = freq;

idx_phi = find((phi_vec) == 0);

idx_theta = find((theta_vec) == 0);

v_dx = {EField_h(idx_phi,idx_theta,:), EField_v(idx_phi,idx_theta,:),EField_a(idx_phi,idx_theta,:)}

for i = 1: numel(v_dx)

y = squeeze(abs(v_dx{i}));

plot(x,((y).^2)/50,'-')

title(num2str(v_dx{i})) % Here I want to iterate over the variable names: EField_h, EField_v, EField_a

xlim([fc-0.5 fc+0.5]);

xlabel('frequency');

ylabel(v_dx{i},''); % Here I want to iterate over the variable names: EField_h, EField_v, EField_a

end

[Stephen23]

Two better approaches:

• instead of looping over the variable names loop over a separate string array of names (which can also includes characters that are not valid in variable names). Basic indexing makes this simple and efficient.
• use fields of a structure instead of separated variables, then simply loop over the fieldnames.

[AY]

I am able to loop over the field names now but not over the contents inside those fieldnames ....fieldnames contain cell arrays how can i access the contents inside the cell array and loop them as well without defining extra variables

v_dx = struct('EField_h', [EField_h(idx_phi,idx_theta,:)], 'EField_v', [EField_h(idx_phi,idx_theta,:)], 'EField_a', [EField_h(idx_phi,idx_theta,:)])

for k = 1: numel(Fields)

y = squeeze(abs(Fields{k})); Here I want to access the values of fields

figure;

plot(x,((y).^2)/50,'-')

title(Fields{k})

xlim([fc-0.5 fc+0.5]);

xlabel('frequency');

ylabel(Fields{k});

end

[Stephen23]

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

S = struct(..)
S.('somefieldname')

Answer 1

[Jan]

v_dx = struct('EField_h', EField_h(idx_phi,idx_theta,:), ...
              'EField_v', EField_h(idx_phi,idx_theta,:), ...
              'EField_a', EField_h(idx_phi,idx_theta,:));
Fields = fieldnames(v_dx);
for k = 1:numel(Fields)
   value = v_dx.(Fields{k});    
   y = squeeze(abs(value));
   ...       

This is called "dynamic fieldnames". The parentheses around the field name are important.

By the way, there is no need to include an array in square brackets. [] is Matlab's operator for concatenating arrays. [x] concatenates x with nothing, so simply write x.