I am new to MATLAB, can anyone help to generate for loop to assign array elements iteratively

I want to generate a for loop to display the elements of the sequence whose indices are specified in the arrays "usedFrequencies" and "unusedFrequencies". (For "usedFrequencies" display '1' for each of the elements), (For "unusedfrequency", display '0' for each of the elements). Find the codes below

%% Parameters 
T = 600;
PRB = 6;
M = 4;
snr = 15;
n_bits = log2(M);
% % RF_spectrum = cell(PRB, T);
RF_spectrum = zeros(PRB, T);
for t = 1:1:T
    usedFrequencies = [1, 3, 5];
    unusedFrequencies = [2, 4, 6];
    for f = 1:1:length(usedFrequencies)
        RF_spectrum(usedFrequencies(1,f),t) = PU_signal_rx(t,1);
        RF_spectrum(unUsedFrequencies(1,f),t) = noise_signal;
    end
    clear noise_signal
end

[Walter Roberson]

You do not assign to noise_signal anywhere, but you clear it. You might have had a noise_signal already existing, but after one iteration of t you clear it, so you cannot complete the second iteration of t