why am I having problems with a string and vector and how to use a *?

hello!

i am trying to load a bunch of .txt files that are in different subject folders, but when i try to run the script with more than one subject, i get errors saying 'Must be a string scalar or character vector'.

The data is all in folders:

/Users/ll/Documents/data_analysis/HCP/seventy/HCA*/ts/cortex.txt

The only changing aspect is the subject number, and I can't figure out how to make it a variable. I have a ton of subjects to do analysis, so it would be great if i didn't indiviudally have to put the subject name in. Does anyone have any ideas? Thanks so so much.

My code:

subj = {'HCA1','HCA2'};  %HCPsubj list
for a = 1:numel(subj)
    (subj{a})
end

D = ['/Users/ll/Documents/data_analysis/HCP/seventy/', subj];

for k = 1:2
    name = sprintf('ts',k); % HCA1, HCA2, etc.
    l = load(fullfile(D,name,'lcortex_run01regPA.txt'));
    v = load(fullfile(D,name,'ventricle_run01regPA.txt'));
    s = load(fullfile(D,name,'spinal_run01regPA.txt'));

Answer 1

[Walter Roberson]

subj = {'HCA1','HCA2'};  %HCPsubj list

D = '/Users/ll/Documents/data_analysis/HCP/seventy/';

for k = 1:length(subj)
    name = subj{k};
    l = load(fullfile(D,name,'lcortex_run01regPA.txt'));
    v = load(fullfile(D,name,'ventricle_run01regPA.txt'));
    s = load(fullfile(D,name,'spinal_run01regPA.txt'));
    ...
end