Issues with order that fprintf prints data

I am trying to print a matrix to a .txt file using fprintf. The code I have written looks like this:

fprintf(fileName,'Header\r\n\r\n');
fprintf(fileName,'%f %f\r\n',matrix);

The matrix looks something like this:

matrix = 1  1
         2  2
         3  3

I want the code to print out exactly what is in the matrix, but instead it is going down each collumn to populate the rows in the text file, like this:

         Header
         1  2
         3  1
         2  3

Any ideas as to why this is occuring?

Answer 1

[Cris LaPierre]

MATLAB stores the data in column-major order by default. The simplest way is to address this is to transpose matrix.

matrix = [1 1; 2 2; 3 3];
fprintf('%f %f\r\n',matrix');

1.000000 1.000000
2.000000 2.000000
3.000000 3.000000

You might also consider using writetable (includes table variable names) or writematrix. It could simplify your code, and will handle writing a table/matrix as expected.

[Peyton Jay]

I'm currently using writematrix to get arround the issue, the main problem is I wanted to be able to add the headers into the text file which is why I was using fprintf

[Cris LaPierre]

What do your headers look like?

If they could be variable names, consider using a table. Try this example.

matrix = [1 1; 2 2; 3 3];
Tmatrix = array2table(matrix);
Tmatrix.Properties.VariableNames = ["Apples","Oranges"]

Tmatrix = 3×2 table
    Apples    Oranges
    ______    _______

      1          1   
      2          2   
      3          3   

With the data formatted correctly as a table, now use writetable(Tmatrix,filename,'Delimiter'," ") to create your file.

[Peyton Jay]

That does it, thank you!