how to add a number to the beginning of a filename

Thank you in advance, I have been trying to figure out a way to do this for awhile and keep getting stuck. I have a folder with an arbitrary amount of files, and I want to just add numbers incrementally to the beginning of the filename. For example:

"filename-a.txt" --> "1-filename-a.txt"

"filename-b.txt" --> "2-filename-b.txt"

Thisis as far as I have gotten, but I realize with this I am just changing a known string to something else:

for k = 1:numel(filepath)
   [~,old,ext] = fileparts(S(k).name);
       new = strrep(old,'filename-a','1-filename-a');
     fpo = fullfile(locationfolder,[old,ext]);
    fpn = fullfile(locationfolder,[new,ext]);
    movefile(fpo,fpn,'f');
end

Answer 1

[Cris LaPierre]

Not knowing what all your variables, are, I think I would simplify to this.

for k = 1:length(S)

fpo = fullfile(locationfolder,S(k).name)

fpn = fullfile(locationfolder,k + "-" + S(k).name);

movefile(fpo,fpn,'f');

end

Just to show you what fpn looks like, see this simple example.

locationfolder = "my/path/";
S(1).name = "filename-a.txt";
S(2).name = "filename-b.txt";

for k = 1:length(S)
    fpn = fullfile(locationfolder,k + "-" + S(k).name)
end

fpn = "my/path/1-filename-a.txt"

fpn = "my/path/2-filename-b.txt"

[Cris LaPierre]

You could also generate all the new file names outside of the loop. This might not get you anything, though, as movefile only accepts scalar inputs, meaning you'd still have to rename the files one at a time.

locationfolder = "my/path/";
S(1).name = "filename-a.txt";
S(2).name = "filename-b.txt";

fullfile(locationfolder,(1:length(S)) + "-" + [S(:).name])

ans = 1×2 string array
    "my/path/1-filename-a.txt"    "my/path/2-filename-b.txt"

[Luke]

This was a very simple solution that worked perfectly, thank you!