Reference to non-existent field 'folder'.

Hi I have this coding to extract data from multiple .nc file, however, during running the code there is an error

Here is the code:

clear all;
clc;
files = dir('*.nc');
outputDirectory = '2023_try'; %create your .asc folder eg: 202201
% Create the output directory if it doesn't exist
if ~exist(outputDirectory, 'dir')
    mkdir(outputDirectory);
end
for k = 1:length(files)
    ncfile = fullfile(files(k).folder, files(k).name);
    %SST = ncread(ncfile, 'SST');
    %SSSanomaly = ncread(ncfile, 'SSS_anom');
    %SSSuncorrected = ncread(ncfile, 'SSS_uncorr');
    SSS = ncread(ncfile, 'SSS_corr');
    Lat = ncread(ncfile, 'Latitude');
    Lon = ncread(ncfile, 'Longitude');
    Data = [Lat(:), Lon(:), SSS(:)] %SSSuncorrected(:), SSSanomaly(:), SST(:)];
    id = Lat>=0 & Lat<=14 & Lon>=95 & Lon<=126;
    Data1 = Data(id,:,:);
%     Data1(isnan(Data1(:,3)),:) = [];
    %Data1(isnan(Data1(:,4)),:) = [];
    %Data1(isnan(Data1(:,5)),:) = [];
    %Data1(isnan(Data1(:,6)),:) = [];
    %id = (Lat >= 0 & Lat <= 14);
    %Data1 = Data(id, :);
    % Extract the filename without the extension
    [~, baseFileName, ~] = fileparts(ncfile);
    % Create the output .asc filename
    outputFileName = fullfile(outputDirectory, [baseFileName '.asc']);
    % Save the data as an ASCII file
    save(outputFileName, 'Data1', '-ASCII');
end


Here is the error:
Reference to non-existent field 'folder'.
Error in SMOS_nc_extract_all (line 10)
    ncfile = fullfile(files(k).folder, files(k).name);

Answer 1

[Jonas]

if there are no .nc files in the current directory, then

files = dir('*.nc');

will be empty, and as consequence

files(k)

will be referring to an empty struct and the field

files(k).folder

will not exist

[MAT NIZAM UTI]

In the current directory, there is .nc file.. but there is still same error..

Answer 2

[Walter Roberson]

In sufficiently old versions of MATLAB, there is no .folder field in the results of dir.

I think .folder was added roughly R2013b