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I have a folder with 1500 images. I need to process the first 200 images(ie, 1 to 200). I used for loop it. But when i run the code i starts from 1,2,3 ... 100. then instead if going for 101th image, its value changes to 1001 , 1002... and so on.

1 view (last 30 days)
for i = start : stop
But i need to continue from 101, 102,... after 100. Kindly help me identify the problem.

Accepted Answer

Stephen23 on 8 Feb 2016
Edited: Stephen23 on 26 Apr 2021
The easiest solution is to use my FEX submission natsortfiles. It fixes the order of an ASCII sort to take into account any numeric values in the strings. Note that it requires the file natsort to work!
It simply sorts a cell array of filenames into the order you want:
S = dir('*.jpg');
S = natsortfiles(S);
for k = 1:200 % first 200 files
F = S(k).name;
... your code
Note that this answer assumes that your files are sequentially numbered without any gaps. If this is not true, then you need to give more information on the filenaming logic.
jeffin on 8 Feb 2016
Edited: Stephen23 on 8 Feb 2016
sir, the problem with me is the following,
My code is as follows,
srcFiles = dir('E:\New Folder\*.tif'); % the folder in which images exists
start = 1 ;
end = 200;
for i = start : end
filename = strcat('E:\New Folder\',srcFiles(i).name);
I = imread(filename);
figure, imshow(I);
i = 1 => srcFiles(i).name = 1.tif
i = 2 => srcFiles(i).name = 2.tif
i = 3 => srcFiles(i).name = 3.tif
and so on... but when
i = 101 => srcFiles(i).name = 1001.tif and
i = 102 => srcFiles(i).name = 1002.tif
But i need this to read 101.tif and 102.tif for i=101 and 102.
Kindly help me.
Stephen23 on 8 Feb 2016
Edited: Stephen23 on 26 Apr 2021
Here is one way of solving your task using my answer:
P = 'E:\New Folder';
S = dir(fullfile(P,'*.tif'));
S = natsortfiles(S);
for k = 1:200
F = fullfile(P,S(k).name);
I = imread(F);
  • you will need to download NATSORTFILES.
  • I changed the loop variable from i to k, because in MATLAB i is the imaginary unit.
  • I used fullfile to create the path strings, which is much more robust than using strcat.

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More Answers (1)

Image Analyst
Image Analyst on 8 Feb 2016
Stephen23 on 9 Feb 2016
Edited: Stephen23 on 26 Apr 2021
Thank you for the links! I think both were picked for PotW, but there are a few differences:
Note that natsorfiles correctly considers the file-names and file-extensions separately.
Image Analyst
Image Analyst on 9 Feb 2016
Stephen, you should notice that first link I gave actually talks about your submission as the "Pick of the Week".

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