Converting to numerical ordering from ASCII ordering

Hi All,

I am stuck trying to get Matlab to process my files in numerical order. When I use dir() and it processes each image in there during a for loop, it processes them according to ascii ordering. How can I get my code to process them in numerical order?

I tried using thr function 'natsort' but apparently on matlab R2015b it doesn't exist!

Here is what my processed images are looking like. Notice the order (1,10,11,12 etc...)

Now reading H:\Documents\o2\Processed Image1.jpg0 The experiment is not complete yet. The number of Black Pixels is: 27

Now reading H:\Documents\o2\Processed Image10.jpg1 The experiment is not complete yet. The number of Black Pixels is: 2

Now reading H:\Documents\o2\Processed Image11.jpg1 The experiment is not complete yet. The number of Black Pixels is: 12

Now reading H:\Documents\o2\Processed Image12.jpg1 The experiment is not complete yet. The number of Black Pixels is: 13

Now reading H:\Documents\o2\Processed Image13.jpg1 The experiment is not complete yet. The number of Black Pixels is: 24

Now reading H:\Documents\o2\Processed Image14.jpg1 The experiment is not complete yet. The number of Black Pixels is: 117

Now reading H:\Documents\o2\Processed Image15.jpg1 The experiment is not complete yet. The number of Black Pixels is: 18

Now reading H:\Documents\o2\Processed Image16.jpg1 The experiment is not complete yet. The number of Black Pixels is: 10

Now reading H:\Documents\o2\Processed Image17.jpg1 The experiment is not complete yet. The number of Black Pixels is: 159

Now reading H:\Documents\o2\Processed Image18.jpg1 The experiment is not complete yet. The number of Black Pixels is: 159

Now reading H:\Documents\o2\Processed Image19.jpg1 The experiment is not complete yet. The number of Black Pixels is: 41

Now reading H:\Documents\o2\Processed Image2.jpg0 The experiment is not complete yet. The number of Black Pixels is: 0

Now reading H:\Documents\o2\Processed Image20.jpg1 The experiment is not complete yet. The number of Black Pixels is: 229

Now reading H:\Documents\o2\Processed Image21.jpg1 The experiment is not complete yet. The number of Black Pixels is: 194

Now reading H:\Documents\o2\Processed Image22.jpg1 The experiment is not complete yet. The number of Black Pixels is: 110

Now reading H:\Documents\o2\Processed Image23.jpg1 The experiment is not complete yet. The number of Black Pixels is: 225

Now reading H:\Documents\o2\Processed Image24.jpg1 The experiment is not complete yet. The number of Black Pixels is: 375

Now reading H:\Documents\o2\Processed Image25.jpg1 The experiment is not complete yet. The number of Black Pixels is: 125

Now reading H:\Documents\o2\Processed Image26.jpg1 The experiment is not complete yet. The number of Black Pixels is: 869

Now reading H:\Documents\o2\Processed Image27.jpg1 The experiment is not complete yet. The number of Black Pixels is: 568

Now reading H:\Documents\o2\Processed Image28.jpg1 The experiment is not complete yet. The number of Black Pixels is: 547

Now reading H:\Documents\o2\Processed Image29.jpg1 The experiment is not complete yet. The number of Black Pixels is: 1121

Now reading H:\Documents\o2\Processed Image3.jpg0 The experiment is not complete yet. The number of Black Pixels is: 5

Now reading H:\Documents\o2\Processed Image30.jpg1 The experiment is not complete yet. The number of Black Pixels is: 1875

Now reading H:\Documents\o2\Processed Image31.jpg1 The experiment is not complete yet. The number of Black Pixels is: 1617

Now reading H:\Documents\o2\Processed Image32.jpg1 The experiment is not complete yet. The number of Black Pixels is: 2108

Now reading H:\Documents\o2\Processed Image33.jpg1 The experiment is not complete yet. The number of Black Pixels is: 1849

Now reading H:\Documents\o2\Processed Image4.jpg0 The experiment is not complete yet. The number of Black Pixels is: 21

Now reading H:\Documents\o2\Processed Image5.jpg0 The experiment is not complete yet. The number of Black Pixels is: 5

Now reading H:\Documents\o2\Processed Image6.jpg0 The experiment is not complete yet. The number of Black Pixels is: 2

Now reading H:\Documents\o2\Processed Image7.jpg0 The experiment is not complete yet. The number of Black Pixels is: 2

Now reading H:\Documents\o2\Processed Image8.jpg0 The experiment is not complete yet. The number of Black Pixels is: 1

Now reading H:\Documents\o2\Processed Image9.jpg0 The experiment is not complete yet. The number of Black Pixels is: 5

any ideas?

many thanks,

Ellis

Answer 1

[Stephen23]

The order returned by dir is not specified by its documentation. This means you need to sort its output data yourself.

There is not inbuilt function to do what you want, but you can use my FEX submission natsortfiles, which I wrote to solve this exact problem of sorting file names, taking into account any numbers in their names:

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

You can use it something like this:

S = dir('*.jpg');
S = natsortfiles(S);
for k = 1:numel(A)
    file = S(k).name;
    ... your code
end