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Stripping outputs from dir function

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big ted
big ted on 28 May 2020
Commented: Steven Lord on 28 May 2020
I have a folder with a bunch of png images:
one.png
two.png
three.png etc.
I read the contents of the folder using the dir command:
fileList = dir;
which returns a structure, the name field of which contains:
'.'
'..'
'one.png'
'two.png'
etc.
I would like to remove the invalid entries generated by the Windows file structure. I am sure there is an easy way to do this!
Seems like it should be possible to do using cellfun, but
str = '.png';
fileList = fileList(cellfun(@contains str, fileList.name));
is invalid.
Creating a loop and using contains seems inefficient, but I don't have too many files:
for ii = 1:length(fileList)
idx(ii) = contains('.png',fileList(ii).name);
end
bizarrely returns idx = 1 0 0 0...
Interestingly, the contains command appears to not work as I expect:
contains('.png','one.png')
ans =
logical
0
which explains why my loop approach doesn't work...
This is a problem I face regularly, so any help would be appreciated!

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Accepted Answer

Fangjun Jiang
Fangjun Jiang on 28 May 2020
fileList = dir('*.png')

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More Answers (1)

big ted
big ted on 28 May 2020
You're kidding me?! I swear I've tried this before with no luck as I couldn't get dir to return an output to a variable if I also provided inputs.
Embarassing, but thanks!

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Steven Lord
Steven Lord on 28 May 2020
You were likely calling dir in its command form.
dir *.png
You can't specify outputs in command form. For that you need function form, but that also requires you to wrap inputs that you want to pass into the function as char vectors using single quotes.
Q = dir('*.png')
See this documentation page for more information.

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