printing nxnxn matrix into a file

Hi,

I have received a .mat file including a 3x3x2 matrix as follows;

****************************

X =

ans(:,:,1) =

1 0 1

1 1 0

0 0 1

ans(:,:,2) =

0 1 1

1 1 0

1 1 1

****************************

I'd like to print my 3x3x2 matrix into a .mat file in the format given in the example above.

It may be a very simple question, but how can I print my matrix to a .mat file in this format?

Thank you.

[Stephen23]

"It may be a very simple question, but how can I print my matrix to a .mat file in this format?"

The question is not simple: MAT files are a binary file format:

https://www.mathworks.com/help/matlab/import_export/mat-file-versions.html

Binary files do not store formatted text. They store numbers as bits.

What is your real goal?

https://xyproblem.info/

https://en.wikipedia.org/wiki/XY_problem

Answer 1

[Image Analyst]

You can't. The .mat file is a proprietary format, and I think it's binary. So the numbers are just in there and it doesn't make any sense to specify a format for them since a .mat file is not something you will ever look at like a text file. You will only use load to retrieve your variable from the .mat file.

Now if you want a text file, you can use fopen(), fprintf(), and fclose.

[melih guneri]

Thank you

Answer 2

[Steven Lord]

It may be a very simple question, but how can I print my matrix to a .mat file in this format?

You're conflating two things. I'm going to make some arbitrary data A and apply the two methods to that data in a temporary directory. A is a random 3-by-3-by-2 array each element of which is an integer between 1 and 10.

cd(tempdir)
A = randi(10, [3 3 2])

A = 
A(:,:,1) =

     9     8     5
     2     3    10
    10    10     6


A(:,:,2) =

     7     5     8
    10     3     9
    10     4     8

Do you want to save your array (a matrix must be 2-dimensional, as per the ismatrix function) to a binary MAT-file? If so use the save function.

save('mymatfile.mat', 'A')
whos -file mymatfile.mat

  Name      Size             Bytes  Class     Attributes

  A         3x3x2              144  double              

data = load('mymatfile.mat')

data = struct with fields:
    A: [3×3×2 double]

disp(data.A)

(:,:,1) =

     9     8     5
     2     3    10
    10    10     6


(:,:,2) =

     7     5     8
    10     3     9
    10     4     8

Or do you want to print the display of this array to a text file? If so I'd use formattedDisplayText to capture the displayed text to a string then use writematrix to write that string to a file.

S = formattedDisplayText(A)

S = 
    "
     (:,:,1) =
     
          9     8     5
          2     3    10
         10    10     6
     
     
     (:,:,2) =
     
          7     5     8
         10     3     9
         10     4     8
     "

writematrix(S, 'mytextfile.txt')
type mytextfile.txt

"
(:,:,1) =

     9     8     5
     2     3    10
    10    10     6


(:,:,2) =

     7     5     8
    10     3     9
    10     4     8
"

If you wanted to add the name of the variable to the string you could do that before writing it to the file.

S2 = replace(S, '(', 'A(')

S2 = 
    "
     A(:,:,1) =
     
          9     8     5
          2     3    10
         10    10     6
     
     
     A(:,:,2) =
     
          7     5     8
         10     3     9
         10     4     8
     "

[melih guneri]

Thank you Steven,

I'll try these solution.

Answer 3

[Hassaan]

% Your 3x3x2 matrix
X = cat(3, [1, 0, 1; 1, 1, 0; 0, 0, 1], [0, 1, 1; 1, 1, 0; 1, 1, 1]);

% Open a new text file for writing
fileID = fopen('matrix_output.txt','w');

% Loop through each 'slice' of the matrix
for k = 1:size(X,3)
    fprintf(fileID, 'ans(:,:,%d) =\n', k);
    for i = 1:size(X,1)
        fprintf(fileID, '\t');
        for j = 1:size(X,2)
            fprintf(fileID, '%d\t', X(i,j,k));
        end
        fprintf(fileID, '\n');
    end
end

% Close the file
fclose(fileID);

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[melih guneri]

Dear Muhammad,

Thank you for your kind answer.

In fact I thought this formatting (ans(:,:,1)= etc.) was automatic printout of an array rather than a specifically formatted output.

Do you think I can print an array to a text file in this format, with a much simpler (built-in) command?

Thank you.

[Voss]

@melih guneri: See https://www.mathworks.com/help/matlab/ref/formatteddisplaytext.html.

[melih guneri]

Thank you Voss