Nicolas - for sure you can add a loop as long as you know what to increment by at each iteration. If we assume an increment of 10 (given your pattern of 00,10,30) then we could wrap your above code in a for loop as
for u=0:10:50
% create the file pattern
filePattern = sprintf('%02d',u);
idx=~cellfun(@isempty,regexp(a,['.+(' filePattern 'k.txt)\>'],'match'));
% if any value in logical array is one then save to b
if any(idx)
b=a(idx)
end
end
Running the above code with your a produces the following output
b =
'Mod1-A-00k.txt' 'Mod1-B-00k.txt'
b =
'Mod1-A-10k.txt' 'Mod1-B-10k.txt'
b =
'Mod1-A-30k.txt' 'Mod1-B-30k.txt'
