How to solve error "access denied" when using mkdir?

Hi,

i want to create a new folder.

It works when I do it like this:

mkdir '\\dbfz-user.leipzig.dbfz.de\user$\jboettner\Documents\HiWi\Matlab\File import\angepasste_Ausgabedatein' Plots

But when i read in the file path (as I use it elsewhere in the script) it does not work:

P = '\\dbfz-user.leipzig.dbfz.de\user$\jboettner\Documents\HiWi\Matlab\File import\angepasste_Ausgabedatein'
mkdir P Plots

I get an error message saying that the access is denied. Is there any way to solve this? As in my view, I doesn't make sense that one would work and for the other one the access is denied.

Answer 1

[Stephen23]

Explanation:

The basic problem is that you are calling MKDIR using command syntax (not function syntax), but are expecting to provide an input argument. That will not work.

Your command syntax:

mkdir P Plots

is exactly equivalent to this function syntax:

mkdir('P','Plots')

but clearly your OS does let you create things in the non-existent folder P.

https://www.mathworks.com/help/matlab/matlab_prog/command-vs-function-syntax.html

Solution:

If you want to call any function with an input argument (not literal text) then use function syntax:

mkdir(P,'Plots')

With a few exceptions (e.g. debugging) you should forget that command syntax exists.

[Jan Böttner]

thanks a lot, works perfectly! Wasn't aware of the syntax difference :)

Answer 2

[Image Analyst]

This is what I'd do

folder = '\\dbfz-user.leipzig.dbfz.de\user$\jboettner\Documents\HiWi\Matlab\File import\angepasste_Ausgabedatein'
if ~isfolder(folder)
    mkdir(folder);
end

What is "Plots" supposed to do and why is it on the line where you're trying to create a folder? Is it a subfolder of the first folder? If so, just add it on:

folder = '\\dbfz-user.leipzig.dbfz.de\user$\jboettner\Documents\HiWi\Matlab\File import\angepasste_Ausgabedatein/Plots'
if ~isfolder(folder)
    mkdir(folder);
end

[Jan Böttner]

In "Plots" i want to save the plots.

My script imports files from a folder, therefore I save that directory into "P".

Then the script runs, plots some stuff and in the end I want to save the plots into a new subfolder called "plots".

As the directory in which the files that should be imported will change, when a different user uses the script, it would be great if the filepath only needs to be changed in one place in the script. That's why I wanted to add "Plots" to "P".

[Image Analyst]

Then you can't hard code the folder like that if it's for different users and P changes somehow. So let's say that you got P somehow for the current user. Then you could just do

mkdir(P, 'Plots');

Or even better;

plotFolder = [P, 'Plots'];
if ~isfolder(plotFolder)
    mkdir(plotFolder);
end

Why is this better? Now you can use plotFolder later on in your code whenever you need to. Otherwise if you just refer to it when you're calling mkdir, you won't have it later when you need it.

Also, another tip is to use fullfile and to never use cd to change the current folder, use fullfile() instead.

https://matlab.fandom.com/wiki/FAQ#Where_did_my_file_go?_The_risks_of_using_the_cd_function.

[Jan Böttner]

thanks for your help and the advice!