How to open file, clear content, rewrite conent and close.

Hi,

I'm trying to open a .dir file (same as a .txt file) clear the content, rewrite the content and then close. The content is different paths to files, which are a combination of numbers and letters. As currently scripted, the .dir file gets rewritten with a series of numbers ...so there is something wrong with the notation, but I'm not sure what. Also, this script creates another level_01 file, but I don't need it to...

for i=1:num_sim
    % Rewrite level_01.dir with new file path for each MC iteration
    DIR_working = sprintf('%s%d','C:\Users\jessi\Desktop\HydrusMC\Simulations\MC_',i);
    
    % Print the file path of HYDRUS-1D input files in LEVEL_01.dir
    DIR=fopen('C:\Users\jessi\Desktop\HydrusMC\LEVEL_01.dir','wt+');
    fprintf(DIR,'%f',DIR_working);
    fclose(DIR);
end

thanks for any suggestions!!

Answer 1

[Walter Roberson]

DIR=fopen('C:\Users\jessi\Desktop\HydrusMC\LEVEL_01.dir','wt+');

That looks for a file named C:\Users\jessi\Desktop\HydrusMC\LEVEL_01.dir . If it does not find it, it creates the file and opens it for reading and writing. If it does find the file, it opens the file for reading and writing and discards all existing content in the file.

    DIR_working = sprintf('%s%d','C:\Users\jessi\Desktop\HydrusMC\Simulations\MC_',i);
    

That is a character vector

   fprintf(DIR,'%f',DIR_working);

%f format is "floating point", but what you are passing in is a character vector. The individual characters in the vector will be treated as numbers (using their Unicode code point), and the resulting integers will be output as floating point numbers. You did not specify any space or commas or other delimiters, so the numbers will all run together in the file.

If you want to output a character string use '%s\n' format.

[Wesser]

Thanks!

Answer 2

[dpb]

DIR_working="C:\Users\jessi\Desktop\HydrusMC\Simulations\MC_"+[1:num_sim].';
writematrix(DIR_working,'C:\Users\jessi\Desktop\HydrusMC\LEVEL_01.dir','FileType','text')