how to extract file name

Hi I am trying to extract a file name but i don´t want to extract it´s entire name.For example if i have 30 people with 3 different expressions each. I name them as 0101.txt...0103.txt,...,3001.txt...3003.txt. How could i extract only the first 2 digits that represent individual person? Thank you.

Answer 1

[per isakson]

If I got you question right

cac = { '0101.txt', '0103.txt', '3001.txt', '3003.txt' };
out = regexp( cac, '^\d{2}', 'match' );
out{:}

outputs

ans = 
    '01'
ans = 
    '01'
ans = 
    '30'
ans = 
    '30'

[yan abr]

i need to continue with another process on this..but at this stage i got your answer. Thank you very much sir.