How to put a header in a txt file?

I'd like to put a header in my .txt file. I have a file with 744 lines like below. And I wanna put on the first line the header 'hora'.

001
002
003
004
005
006
...
744

Answer 1

[Akira Agata]

Straight-forward solution would be like this:

% Read the file
fid = fopen('yourData.txt','r');
str = textscan(fid,'%s','Delimiter','\n');
fclose(fid);

% Add your header
str2 = [{'hola!'}; str{1}];

% Save as a text file
fid2 = fopen('output.txt','w');
fprintf(fid2,'%s\n', str2{:});
fclose(fid2);

[shobhit pipil]

Hi,

I am trying to implement your code for multiple text files as input and preserve the file name for each output files.

But I am not able to do that would you please suggest the required corrections to your solution.

Thanks

[Akira Agata]

OK.

Assuming your text files are stored in /Input folder and there is an empty /Output folder, the following code will apply it for all the text files and save them in the /Output folder.

fileList = dir('Input/*.txt');

for kk = 1:numel(fileList)
    % Read the file
    fid = fopen(['Input/',fileList(kk).name],'r');
    str = textscan(fid,'%s','Delimiter','\n');
    fclose(fid);
    
    % Add your header
    str2 = [{'hola!'}; str{1}];
    
    % Save as a text file
    fid2 = fopen(['Output/',fileList(kk).name],'w');
    fprintf(fid2,'%s\n', str2{:});
    fclose(fid2);
end

[shobhit pipil]

Hi Akira Agata,

Thanks for your solution I am now able to see that data is being extraced and saved into files, while name of the files preserved. Yet the records return in cell and I will convert that to matrix as my model takes data as float and header as string.

Thanks

[shobhit pipil]

Hi Akira Agata

Now I am using fscanf to read float data from text file, what subsequent code modification do I need to implement as I told earlier that I want to keep first line string and remaining data as float.

% line 20 - str2 = [{'18900101'}; str(:)];

returns 2x1 matrix, where 18900101 saved in 1x1 position and str saved in 2x1 matrix position (all records in single cell)

thanks

Shobhit

[Akira Agata]

Hi Shobhit-san,

Sorry, I don't catch your concern correctly.

Do you want to add a header in a txt data file (as described in the original question)?

Or, do you want to read txt data file as a numeric array?

Anyway, I believe the following slightly modified code can do both of them. I hope this will be some help to address your problem!

fileList = dir('Input/*.txt');
for kk = 1:numel(fileList)
    % Read the file
    fid = fopen(['Input/',fileList(kk).name],'r');
    str = textscan(fid,'%s','Delimiter','\n');
    fclose(fid);
    
    % Convert data into numeric matrix
    data = str2double(str{1});
    
    % ----------------------------------------------------
    % Do something by your model which takes data as float 
    % ----------------------------------------------------
    
    % Add your header
    str2 = [{'hola!'}; str{1}];
    
    % Save as a text file
    fid2 = fopen(['Output/',fileList(kk).name],'w');
    fprintf(fid2,'%s\n', str2{:});
    fclose(fid2);
end

[shobhit pipil]

Thanks