How to change extension of selected file extensions in a directory?

Hi, I'm looking to change all the .s2p file extensions in my working directory into .txt. However, I'm having a hard time doing this. I though I'd be able to use

[filelocation, name, ext] = fileparts(files(id))

But matlab tells me the input must be a row of vectors of characters or string vector - I am not understanding exactly how this functions.

Here's my code as it stands - where should I be going next?

% Converts all given file extensions in a directory

convertfrom = '.s2p';
convertto = '.txt';

% Gets all files of type in current dir
filesnames = "*." + convertfrom;
files = dir(filesnames);

% Loops through each
for id = 1:length(files)
    % Get the file name, ext etc
    [filelocation, name, ext] = fileparts(files(id))

end

Answer 1

[Image Analyst]

Try this:

% Specify the folder where the files live.
myFolder = pwd; % or 'C:\Users\yourUserName\Documents\My SP2 files'; or whatever.
% Check to make sure that folder actually exists.  Warn user if it doesn't.
if ~isfolder(myFolder)
	errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
	uiwait(warndlg(errorMessage));
	return;
end
% Specify the old/current extension.
oldExtension = '.sp2';
% Specify the desired extension
desiredExtension = '.txt';
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(myFolder, sprintf('*%s', oldExtension)) % Change to whatever pattern you need, like '*.sp2'
% Get a file listing of files in myFolder from the operating system:
theFiles = dir(filePattern);
% Now loop over all found files, renaming each in turn with the new desired extension:
for k = 1 : length(theFiles)
	% Get the input filename.
	baseFileName = theFiles(k).name;
	fullInputFileName = fullfile(myFolder, baseFileName);
	% Get the output filename
	fullOutputFileName = strrep(fullInputFileName, oldExtension, desiredExtension);
	fprintf(1, 'Now renaming %s\n          to %s\n', fullInputFileName, fullOutputFileName);
	% Now do the actual renaming:
	movefile(fullInputFileName, fullOutputFileName);
end

code adapted from the FAQ. Adapt further as needed.