How do I replace elements of an array with letters?

Hi, I have an array called 'labels_I03' which is filled with zeros, and I am trying to replace the elements of this array with either 'N' or 'A' based on whether the index of the array element is part of a separate vector called 'abnormal_cycles_I03'. I am currently using a 'for' loop as shown below, but this does not seem to be working. It just returns an array full of zeros. Any suggestions would be greatly appreciated, thanks in advance.

labels_I03 = categorical(zeros(1, number_cycles));
abnormal_cycles_I03 = [128];
for i = number_cycles - 1
    if ~ismember(i, abnormal_cycles_I03)
       labels_I03(i) = 'N';
    else
       labels_I03(i) = 'A';
    end
end

Answer 1

[Adam Danz]

Sounds like you're describing this,

number_cycles = 10; 
labels_I03 = categorical(repmat({'N'},1,number_cycles)); % set all as N
abnormal_cycles_I03 = [2,4,9] 

abnormal_cycles_I03 = 1×3

2 4 9

labels_I03(abnormal_cycles_I03) = categorical({'A'}) % fill in A's

labels_I03 = 1×10 categorical array
     N      A      N      A      N      N      N      N      A      N