grouping files together by name

I would like to iterate through a list of PNG files in a folder (inputdir) and group them based on their file name.

The png filenames end in a format like xxx.01.001.png, xxx.01.002.png... xxx.01.256.png, where xxx is irrelevant.

and I would like to group and move the 256 png files into one folder in a directory like inputdir/01

And repeat the same for other groups like xxx.02.001.png, xxx.03.001.png and so forth

How would this be accomplished? I am trying to code the solution but I am stuck.

cd inputdir
S = dir(fullfile(inputdir,'*.PNG'));
for k = 1:numel(S)
    fnm = fullfile(inputdir,S(k).name);
    newj = % some code here
    if j ~= newj
        mkdir(string(newj));
        j = newj;
    end
end

Answer 1

[Image Analyst]

You'll need to parse the filenames then sort them by whatever number you want to sort them by. You can use fileparts() and strsplit() to break the filename into parts. Here is a start:

S = dir(fullfile(inputdir,'*.PNG'))
allFileNames = {S.name};
for k = 1 : length(allFileNames)
	thisName = allFileNames{k};
	[~, baseFileNameNoExt, ext] = fileparts(thisName);
	if ~contains(baseFileNameNoExt, '.')
		continue; % Skip names with no dot in them.
	end
	fprintf('Processing %s.\n', baseFileNameNoExt);
	nameParts = strsplit(baseFileNameNoExt, '.')
end

[MJ]

Thank you so much!

Answer 2

[Simon Chan]

Following code assumes all your png files are inside the working directory and the filename format are xxxx.00.000.png.

clear; clc;
myFolder = 'C:\Users';                              % Your working directory
S = dir(fullfile(myFolder,'*.png'));
filename = {S.name};
filename_split = cellfun(@(x) strsplit(x,'.'),filename,'UniformOutput',false);
filename_combine = vertcat(filename_split{:});
foldername = unique(filename_combine(:,2));
cellfun(@(x) mkdir(fullfile(myFolder,x)),foldername);
cellfun(@(x,y) movefile(fullfile(myFolder,x),fullfile(myFolder,y)),filename,filename_combine(:,2)');