How to force Matlab to read files in a folder serially?

Question

I have files in a folder that are numbered from writer_1 to writer_20. I wrote a code to read all the files and store them in cells. But the problem is

Answer 1

Approach #1

%// From your code
folders = dir(Path_training);
folders(ismember( {folders.name}, {'.', '..'}) ) = []

%// Convert folders struct to a cell array with all of the data from dir
folders_cellarr = struct2cell(folders)

%// Get filenames
fn = folders_cellarr(1,:)

%// Get numeral part and sorted indices
num=str2double(cellfun(@(x) strjoin(regexp(x,['\d'],'match'),''), fn(:),'uni',0))
[~,ind] = sort(num)

%// Re-arrange folders based on the sorted indices
folders = folders(ind)

Approach #2

If you would like to avoid struct2cell, here's an alternative approach -

%// Get filenames
fn = cellstr(ls(Path_training))
fn(ismember(fn,{'.', '..'}))=[]

%// Get numeral part and sorted indices
num=str2double(cellfun(@(x) strjoin(regexp(x,['\d'],'match'),''), fn(:),'uni',0))
[~,ind] = sort(num)

%// List directory and re-arrange the elements based on the sorted indices
folders = dir(Path_training);
folders(ismember( {folders.name}, {'.', '..'}) ) = []
folders = folders(ind)

Please note that strjoin is a recent addition to MATLAB Toolbox. So, if you are on an older version of MATLAB, here's the source code link from MATLAB File-exchange.