Why dir function is creating additional files while creating a structure? how to ignore it?
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Daniel Vainshtein on 27 Mar 2019
Answered: Steven Lord on 28 Mar 2019
Im trying to make a loop that reading all the files in a choosen folder, I use the dir function to make list of the names of the files and to iterate this list:
files = dir('folder');
for k =1:length(files)
I = imread(files(k).name);
But there is always an error:
Error using imread (line 347)
Cannot open file "." for reading. You might not have read permission.
When I open my structure named "files" there is 2 new rows that the dir function creates in addition to all the other files in that structure:
the first file named '.' and the second '..', those files not exist in the original folder, what to do to erase them or ignore them permanently?
Catalytic on 27 Mar 2019
Edited: Catalytic on 27 Mar 2019
Do a more specific search, like
files = dir('folder/*.jpg');
Or, just throw the first 2 away
files = dir('folder');
More Answers (1)
Steven Lord on 28 Mar 2019
If you're calling imread on the output of dir, you probably want to first check that the entry you're trying to read isn't a directory. You can do this all at once using the isdir field of the struct array returned by dir.
D = dir();
numberOfEntriesPreTrim = numel(D);
D = D(~[D.isdir]);
numberOfEntriesPostTrim = numel(D);
numberOfDirectories = numberOfEntriesPreTrim-numberOfEntriesPostTrim;
for whichfile = 1:numberOfEntriesPostTrim
fprintf('File %d is %s.\n', whichfile, D(whichfile).name)
fprintf('Printed %d of %d entries in pwd (%d are directories.)\n', ...
numberOfEntriesPostTrim, numberOfEntriesPreTrim, numberOfDirectories);
Note that '.' and '..' are not printed by the fprintf statement. They were trimmed because they're directories, but they still count for the last fprintf statement.
I needed to wrap D.isdir in square brackets because it creates a comma-separated list. The square brackets concatenates all the elements of that list into a vector.
As for what . and .. are, on the operating systems on which MATLAB is currently supported they are the current directory and the parent directory, respectively.
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