What's wrong with my code for " rename a bunch of files in a folder "

Hi everyone , I want to rename a bunch of files in a folder ,

here is code

clear;clc;
str = dir('C:\Users\user\Desktop\結果圖\*.jpg'); % folder
strx = struct2cell(str);
sn = length(strx(1,:));
for ix = 1:sn
    newname=sprintf('0%d.jpg',ix);
    movefile(strx{1,ix},newname);
end

it was work , but recently it can not work and shows Error massage

??? Error using ==> movefile
Cannot copy or move a file or directory onto itself.

Why it was work , but it is not now .

ps.

if the first file in the folder is named "01.jpg" then the error is

    ??? Error using ==> movefile
    Cannot copy or move a file or directory onto itself.

if the first file in the folder is named "02.jpg" then the error is

??? Error using ==> movefile
No matching files were found.

Answer 1

[Sean de Wolski]

I get this error when the filename is the old filename is the same as the new filename:

movefile('A.mat','A.mat')

Error using movefile
Cannot copy or move a file or directory onto
itself.

If you don't want to rename all of the files, i.e. the ones that already have the new name are all set, then just skip that iteration

for ix = 1:sn
  newname=sprintf('0%d.jpg',ix);
  if ~isequal(strx{1,ix},newname) % if the names are different
      movefile(strx{1,ix},newname);
  end
end

[Tai-i]

it still get error

??? Error using ==> movefile
No matching files were found.

[Sean de Wolski]

This means it's trying to move a file that doesn't exist:

movefile('HelloWorld.mat','A.mat')

Run the following:

dbstop if error

Which will stop with the debugger when the error is thrown so you can inspect the filename that does not exist.