The problem about dir function

hi every one:

when I use dir function to get the same type files of a file, (the file name is 10.png, 20.png, 50.png, 100.png, 200.png, 300.png, 1000.png), then I find the sequence is 10.png, 100.png, 1000.png, 20.png, 200.png.....

but what I want to get is the sequence like 10.png, 20.png, 50.png, 100.png, 200.png, 300.png, 1000.png

so please give me some suggestion or any help

thanks a lot

[Stephen23]

A simple solution is to use my FEX submission natsortfiles

http://de.mathworks.com/matlabcentral/fileexchange/47434-natural-order-filename-sort

>> S = dir('*.txt');
>> S.name
ans =
    '1.txt'
ans =
    '10.txt'
ans =
    '2.txt'
>> S = natsortfiles(S); % alphanumeric sort by filename
>> S.name
ans =
    '1.txt'
ans =
    '2.txt'
ans =
    '10.txt'

Answer 1

[Jan]

The most practical method is to use "0010" instead of "10". Then the numerical order equals the lexicographical order.

While there are some FEX submissions for "natural sorting", you can sort the names manually also:

List = dir('*.png');
Name = {List.name};
S = sprintf('%s,', Name{:});    % '10.png,100.png,1000.png,20.png, ...'
D = sscanf(S, '%d.png,');       % [10; 100, 1000; 20; ...]
[sortedD, sortIndex] = sort(D); % Sort numerically
sortedName = Name(sortIndex);   % Apply sorting index to original names

[petter]

Thanks a lot

Indeed I use the practical method mentioned by you, and solve the problem

I can,t understand clearly the method that you introduce.

Answer 2

[David Young]

You could do something like this:

dstruct = dir('*.png');
names = {dstruct.name};
maxlen = max(cellfun(@length, names));
padname = @(s) sprintf(['%0' num2str(maxlen) 's'], s);
namesPadded = cellfun(padname, names, 'UniformOutput', false);
[~, sortOrder] = sort(namesPadded);
dstruct = dstruct(sortOrder);

The structure is now in the order you want. To see this, you can execute

disp({dstruct.name})

[petter]

Thanks to David

your method is so clever,I like it.

And I use it to absolutely solve my problem.

Thanks again.