what is the output type of a nagative fullfill function result

Hi Guys

I am using the fullfill function as followig :

dat_dir = fullfile(uigetdir ('select the subfolder for dat file'), '*.txt' );
if convertCharsToStrings(dat_dir) ~= " \*.txt"
    dat= dir(dat_dir);
end

this will help me in other way , if i did not select the subfolder , to check the result of fullfile(uigetdir ('select the subfolder for dat file'), '*.txt' ) which i found \*.txt .

The problem in other words , i found that convertCharsToStrings(dat_dir) in the workspace is equal to " \*.txt" but when i debug it i found it is not equal to " \*.txt".

this is the error msg

Error using dir

Invalid path. The path must not contain a null character.

How should i test the negative result of fullfile function ? And why the if convertCharsToStrings(dat_dir) == " \*.txt" is return 0 although i can see in the workspace convertCharsToStrings(dat_dir) equal to " \*.txt"

[Jan]

"fullfile", not "fullfill".

Answer 1

[Jan]

What is the purpose of the leading space in " \*.txt"?

What does "if i did not select the subfolder" mean? Which subfolder? Do you mean, that you press 'Cancel' in the dialog? Then uigetdir() does not reply a space, but a numerical 0. Do not use a 0 as input for fullfile.

folder = uigetdir('select the subfolder for dat file');
if ~ischar(folder)  % User pressed the Cancel button
   folder = cd;     % Is this wanted? Or: return?
end
dat = dir(fullfile(folder, '*.txt'));

Does this work as wanted?

[Nidhal Bouzouita]

first of all i really appreciate your help so thx a lot :)

the goal is to filter some files for exple the files with extension *.txt from a selected sublofder (we can assume its a folder), i want to test if the user clicked ok or cancel because after that i will use those files with other files so i need to know the result action of the user ( OK or cancel). thats why i tested on the fullfile return function , to know the result of the filter.

in the above code ~ischar(folder) means the user did not press ok , isn't it ? if it the case why should i filter the fodler with *.txt files . i mean the goal is only using the dat if the select the folder (he did not cancel i mean ) ? could you please explain it a litte bit because i think with the above we still assign the dat even in case of cancellation

[Nidhal Bouzouita]

maybe to just modify it as following

folder = uigetdir('select the subfolder for dat file');
if ischar(folder)  % User pressed the Cancel button
    dat = dir(fullfile(folder, '*.dat'));     % Is this wanted? Or: return?
end

there any cons ?

[Jan]

in the above code ~ischar(folder) means the user did not press ok

Yes, if the user presses "Cancel", uigetdir replies a numerical 0.

The code of your former comment looks fine. Then dat remains undefined, if the user has pressed cancel. If you care for this case, the code should run.