Numerate lines to a text file

i write this matrix to a .txt file and i would like to numerate the lines, for example :

1 5 1 6

2 1 2 8

3 1 3 15

....

50 2 1 10

51 2 2 20

52 2 3 13

....

Please will someone help me?

Answer 1

[sixwwwwww]

Here is an example for your problem:

A = rand(100, 3);
num = 1:100;
B = [num' A];
disp(B)
dlmwrite('filename.txt', B, '\t');

In case you don't know the size of matrix you want to numerate then you can do like this:

[m, n] = size(YourMatrix);
num = 1:m;

I hope it helps

Answer 2

[Vivek Selvam]

Hi George

A more rudimentary C like approach is as follows:

[rows cols]         = size(A);
formatSpecRowNum    = '%3.2d ';
formatSpec          = '%5.4f ';
formatSpecNewline   = '\n';
fileID              = fopen('myFile.txt','w+');
for i = 1:rows
    fprintf(fileID,formatSpecRowNum,i);
    for j = 1:cols
        fprintf(fileID,formatSpec,A(i,j));
    end
    fprintf(fileID,formatSpecNewline);
end
fclose(fileID);

Answer 3

[Azzi Abdelmalek]

If A is your nx3 array

c1=1:size(A,1)
A=[c1; A']
fid=fopen('filename.txt','w')
fprintf(fid, '%d   %d   %d   %d \r\n',A);
fclose(fid)