What's wrong with my preallocation of images?

folders = dir("photos");
folders = string({folders.name});
folders = folders(~startsWith(folders,"."))

% Preallocate the structure crashImages
crashImages(length(folders)) = struct("Name",folders(end),"Images",cell(1));

for k = 1:length(folders)
    photos = dir("photos\" + folders(k));
    photos = string({photos.name});
    photos = photos(~startsWith(photos,'.'));
   
    % preallocate the cell array images
   
    images = cell(length(photos),1);

    for kk = 1:length(photos)
        im = imread("photos\" + folders(k) + "\" + photos(kk));
        images{kk} = im;
    end
    
    crashImages(k).Name = folders(k);
    crashImages(k).Images = images;
    
    clear images
end

crashImages

I get the error that the cell arrays in the Image field do not have the correct sizes. What could be the problem?

[Catalytic]

It is generally more informative to copy/paste your error messages (all of them) than to summarize them in your own words. That way, we can see for example what line of code was to blame.

[Stephen23]

Simpler and more robust than using startsWith:

S = dir("photos");
folders = setdiff({S.name},{'.','..'});

Note that you can easily use the same structure that dir returns:

S = dir('photos');
S(ismember({S.name},{'.','..'})) = [];
for k = 1:numel(S)
    ...
    S(k).image = images;
end

Also you should use fullfile rather than concatenating strings together.

"I get the error that the cell arrays in the Image field do not have the correct sizes. What could be the problem?"

If you don't show us the complete error message then we have to guess what the problem is.

Answer 1

[Matt J]

Maybe you meant to have,

crashImages(length(folders)) = struct("Name",folders{end},"Images",cell{1});

[Iana Ladygina]

Thank you for your response. The problem is related to the following line of code:

images = cell(length(photos),1);

It shows the incorrect size of images.

[Walter Roberson]

I recommend that you learn how to use fullfile()

[Iana Ladygina]

Sorry, may be I don't understand it well, but how is fullfile() function related to the preallocation?

[Walter Roberson]

Your file reference is coming out wrong, so dir is returning empty, so length is 0, so images would be an empty cell. You then interpreted that as being the incorrect size.