Reading data from a large text file into matrix

Hello, so I am trying to read data from a really large text file and put it into a matrix. I have 2 problems:

1) Using a test file that only has 3 lines of the large text file, I am able to get the data into a matrix, but I can't use the data because they're all cell arrays? I want to be able to use the numbers and strings I read from the large text file to do calculations. This is the sample text file:

N080602ABX     000000BARRICK GOLD CORP   067901108 M
Q080602ABX     00172500399200040350010006
Q080602ABX     07005200400000040350002006

The data is grouped such that I need to separate parts of each line to get what I want, e.g. 001725, 39920, 40350, and so on.

This is my code:

function [ C nLines ] = ret(  )
% Returns C matrix with the data

fileID = fopen('ABX.txt');
nLines = 0; %get total number of lines to specify dimensions of matrix later
while (fgets(fileID) ~= -1),
  nLines = nLines+1;  
end
fclose(fileID);

fileID = fopen('ABX.txt');
    C = textscan(fileID, '%1s %6s %*8s %6s %7s %7s %*[^\n]');
%    C = textscan(fileID, '%1s %6d %*8c %6d %7d %7d %*[^\n]');
% I didn't use the above line because I couldn't access the individual cells
% of the matrix without reading the text file as all strings
fclose(fileID);

A = C{1};
B = C{2};
D = C{3};
E = C{4};
F = C{5};
C = [A B D E F]; 
%I couldn't access the individual cells of the matrix without doing this

end

2) Also, when I run my code on the large text file, matlab crashes. Is there anything I can do to clean up my code?

Answer 1

[per isakson]

This code reads the second and third lines

>> cac = cssm() 
cac = 
    [2x1 char]    [2x6 char]    [2x1 uint32]    [2x1 uint32]    [2x1 uint32]
>>

where

    function  cac = cssm()

12345678

Q080602ABX 00172500399200040350010006

        frm = '%1c%6c%*8c%6u%7u%7u%*[^\n]';
        fid = fopen( 'cssm.txt', 'r' ); 
        cac = textscan( fid, frm, 'Delimiter', ''          ...
                      , 'Whitespace', '', 'Headerlines', 1 );  
        fclose( fid );

    end

and cssm.txt contains your three sample lines.

You need to handle the first line separately in one way or another.

.

--- in response to comment ---

    >> [ txt, num ] = cssm()
    txt =
    Q
    Q
    num =
           80602        1725       39920       40350
           80602       70052       40000       40350
    >> num(2,2)
    ans =
           70052    
    >> sum( num )
    ans =
          161204       71777       79920       80700

where

    function  [ txt, num ] = cssm() 
        cac = cssm_();
        txt = cac{1};
        num = [ cac{2}, cac{3}, cac{4}, cac{5} ];
    end
    function  cac = cssm_()

12345678

Q080602ABX 00172500399200040350010006

        frm = '%1c%6f%*8c%6f%7f%7f%*[^\n]';
        fid = fopen( 'cssm.txt', 'r' ); 
        cac = textscan( fid, frm, 'Delimiter', ''          ...
                      , 'Whitespace', '', 'Headerlines', 1 );  
        fclose( fid );
    end

[Louise]

Hi, my problem is that cac is now a 1x5 matrix and I don't know how to access the individual elements in each row, e.g 70052

[per isakson]

You have to separate text, e.q. "Q", from the "numerical" strings.

Either, you read the file as text and convert to numeric in a second step or you do it in one step with the help of conversion specifiers in the format string.