how can ı solve this error ? Error using fprintf Invalid file identifier. Use fopen to generate a valid file identifier.

clear all;clc;
y=[2 3 4 5;5 6 7 8]
fid=fopen('myfile.txt','wt');
fprintf(fid,'%d,%d\n',y);
fclose(fid);

Answer 1

[Jan]

Check the success of fopen in every case, under all circumstances, ever, nerver omit this test:

filename = 'myfile.txt';
filepath = cd;
file     = fullfile(filepath, filename);
fid = fopen(file, 'wt');
if fid==-1
  error('Cannot open file for writing: %s', file);
end

I guess you do not have privileges to write to the current folder.

[Walter Roberson]

In particular if you are using Windows and you clicked on the icon to start matlab and you have not changed directory since you started then you will be in a directory that you do not have write permission.

[Burak Kurt]

thank you for quick solution :)

[Yu-Ming Chen]

Thank you Jan Simon. You saved me.

[Stephen23]

Even better is to get the very informative message returned by fopen:

[fid,msg] = fopen(file, 'wt');
assert(fid>=3,msg)

Answer 2

[Caio Vaz Rimoli]

Just brief comment: I also got this error because I ran out HD memory.

Answer 3

[Aparna Komarla]

Creating the directory you are storing the files/data in first might help!