How to save the output value from struct H(Index).b to variable f ?

Code:

Index=1;

if(H(Index).e > 0.5 && H(Index).c > 0.9 || H(Index).c < 0.5 && H(Index).en > 0.2 && (H(Index).x)>10)

f=H(Index).b;

fprintf("Embedding Region %d\n",f);

Index=Index+1;

Explain:

Actually the H struct has five field and based on the if condition it display the output correctly but the issue is, all the values is not stored in variable ' f ', only the last value is shown as f value? How to store all the selected values to the variable f? If i declare f as array then also the last value is alone store in f? where am lagging am not getting? Can anybody suggest solution.

Thanks in Adavnce.

[Divyanshu]

Hi Aberna,

I understand that you are trying to iterate through ‘H’ and store each element’s ‘b’ field’s value into the variable ‘f’.

Here is a sample script which you can refer to:

Index = 1;
while Index<=3
    %Column vector f is created in which "Index"
    %holds the corresponding iteration's value of field b 
    
    % if condition
        f(Index,1) = H(Index).b;
        fprintf("Embedding Region %d\n",f(Index,1));
    % end

    Index = Index+1;
end

Please refer the following documentation for better understanding:

Array Indexing - MATLAB & Simulink (mathworks.com)

[Aberna P]

Thanks for the response divyanshu. But it doesnt work, it print 1 as the output for nymber of n times. its not storing the b values in f.

[Dyuman Joshi]

@Aberna P Could you please attach the whole code you are working with?

Answer 1

[akshatsood]

Hi Aberna,

I understand that you want to store the output from a struct 'H' into a variable 'f'. To achieve this, you need to declare the variable 'f' as a vector with the same size as 'H'. Based on the provided code snippet and the information given in the question, I have assumed the existence of a struct 'H' and prepared a script to guide you through the correct approach. Please refer to the code snippet attached herewith.

% create an empty struct array
H = struct('e', [], 'c', [], 'en', [], 'x', [], 'b', []);

% generating random values for each field
for i = 1:5
    H(i).e = round(0.5+rand(1), 1);
    H(i).c = round(1+rand(1), 1);
    H(i).en = round(rand(1), 1);
    H(i).x = round(10*rand(1), 1);
    H(i).b = round(rand(1), 1);  
end

% preallocating f to store the output
f = zeros(1,5); 
Index = 1;

while Index <= 5  
    if (H(Index).e > 0.5 && H(Index).c > 0.9) || ((H(Index).c < 0.5 && H(Index).en > 0.2) ...
            && (H(Index).x > 10))
        
        f(Index) = H(Index).b;            
        fprintf("Embedding Region %.1f\n",f(Index));
    end
    Index=Index+1;
end

Now, the variable 'f' will store the value corresponding to the field 'b' in the struct 'H'. Since the complete code was not provided, I have made assumptions to illustrate the correct methodologies. Update the above code as per your needs.

I hope this helps.