Easiest way to read a txt file(with char and numbers) into a numerical array/matrix?

Hi all, really frustrated with this one problem. Basically there is a txt file that has lines of code, code being a mixture of letters and numbers (of different length) WITHOUT commas and spaces in between them ie: one code from the txt file is X32W21039A23

I need to read it into an numerical array/matrix so that it will be easy for me to manipulate it, AND I have to replace the letters with their corresponding numbers from a table. This is what I currently have

fid = fopen('upcs.txt');
mat = [];
if fid == -1
  disp('File open was not successful')
else 
    while feof(fid) == 0
        % Read contents of file and store into a matrix
        aline = fgetl(fid);
        [P] = sscanf(aline, '%s');
        if length(A) == 12
            mat = [mat P];
        end
    end
    codes =reshape(mat, length(mat)/12, 12)

Basically I have removed all the lines from the txt file that were not 12 figures long (I can do that), and transferred the remaining lines into a character array, 'mat'. However, mat is a character array, not a numerical one. I've tried such functions as cell2mat and str2num, but to no avail, for I believe the codes are treated as cells or strings, rather than numbers. I believe I need to put spaces between the strings in the array.

So to sum up, can anyone help me easily transfer the codes in the txt file into a manner such that I can easily manipulate it like a vector of numbers ie: [1 2 3] thanks

[Walter Roberson]

How should your X32W21039A23 be broken up? 'X' 32 'W' 1039 'A' 23 ? You indicate the numbers are of varying length and that the total length is 12: do the numbers each go until the next letter? Does the line always start with a letter? Are there always 3 pairs of letter then number ?