how to use for loop ?

one of my friend help me to write this code to read one text file which works perfect. but now I want to use this code to process multiple text files from one same folder. I am attaching 3 files for example. I am not able to use perfect loop for all these files.

 content =  fileread( 'L3_tropo_ozone_column_apr14.txt' ) ;
filename = char('L3_tropo_ozone_column_apr14.txt')
 % - Remove first space on all data rows.
 content = regexprep( content, '(?<=[\r\n]) ', '' ) ;
 % - Split by "lat = ..." separator.
 blocks = regexp( content, '\s+lat[^\r\n]+', 'split' ) ;
 % - Extract header from block 1.
 pos = regexp( blocks{1}, '\)\s+\d', 'start' ) ;
 header = blocks{1}(1:pos) ;
 blocks{1} = blocks{1}(pos+1:end) ;
 % - Merge blocks, remove \r\n, replace spaces by 0s.
 blocks = [blocks{:}] ;
 blocks = regexprep( blocks, '[\r\n]', '' ) ;
 blocks(blocks == ' ') = '0' ;
 % - Convert to 120x288 numeric array.
 data = reshape( sscanf( blocks, '%3d' ), 288, 120 ).' ;

[Stephen23]

This is explained quite well in the MATLAB documentation:

https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html

and a thousand times on this forum:

https://www.mathworks.com/matlabcentral/answers/57446-faq-how-can-i-process-a-sequence-of-files

Answer 1

[pruth]

finally I somehow I did

 O3_data_folder = 'C:\Users\Myself\Dropbox\prithvi_project\o-3';
cd(O3_data_folder);
%%open files in the data folder
temp = dir();
O3filenames = [];
%%%for the program to not read .files
flag_1 = 0 ;
for i = 1:numel(temp);
if (strncmp(temp(i).name, '.', 1) == 1);
flag_1 = flag_1 +1 ;
else
O3filenames{i-flag_1} = temp(i).name ;
end
end
  for file = 1:size(O3filenames,2);
fname = char(O3filenames(file));
fid= fopen(fname(file));   % creating file id
content = fileread(fname) ;
% - Remove first space on all data rows.
content = regexprep( content, '(?<=[\r\n]) ', '' ) ;
% - Split by "lat = ..." separator.
blocks = regexp( content, '\s+lat[^\r\n]+', 'split' ) ;
% - Extract header from block 1.
.
.
.end

Answer 2

[KSSV]

This question is discussed to death in mathworks.

https://in.mathworks.com/matlabcentral/answers/130841-read-all-text-files-in-folder-nonsequential

https://in.mathworks.com/matlabcentral/answers/224348-how-can-i-read-all-text-files-in-a-folder-without-making-a-struct