Error: Cannot create output file

In a matlab script printing multiple figures, I am trying to save as each figure as a .png image. I am doing so by using the print function. When testing the print function, I get the following:

>> print('newfile','-dpng')

Error using name (line 102)

Cannot create output file '.\newfile.png'.

Error in print (line 200) pj = name( pj );

Could anyone tell me how to fix this?

Thanks a lot.

Answer 1

[Jan]

The error message means, that the file "newfile.png" cannot be created in the current folder. Either this file is existing already, but write-protected or in use. Or you do not have write permissions in the current folder.

Prefer to define file names including the complete path, because you cannot control if a timer or GUI callback uses cd to change the current folder. Relying on the current folder to be, where it is expected, is not reliable.

[fawkok]

Thanks a lot! With the complete path it is working. I have a follow-up question: is it possible to include in the filename a variable. Say, I print 10 graphs iteratively and want each graph to be called 1, 2, 3, etc. How do I do this? Is it possible with the num2str function?

[Walter Roberson]

Yes you can use num2str and concatenation, but it is usually better to use sprintf and fullfile()

[Jan]

for k = 1:10
  file = fullfile(folder, sprintf('File%03d.jpg', k));
  disp(file);
end

See also: https://www.mathworks.com/matlabcentral/answers/57446-faq-how-can-i-process-a-sequence-of-files