Error creating using xlswrite function

Hello all,

I am not an expert in matlab and I am stack right now in a part of my code. The idea is that in my company does not use matlab too much so everything I process in matlab I require to output in excel. '

I work with IFILES from AVL, which are a not common files from combustion analyser software. For these files I use a function developed by matlab:

https://uk.mathworks.com/matlabcentral/fileexchange/31709-load_ifile-filename-offset_correction

Normally, I work with a high number of IFILES and therefore, I am trying to automated the script as now I have to do it manually. Right now, I am looping through a folder, acquiring the names of the files, loading these files load_ifile function and saving the variables I am interesting in cell array as IFILE will load to work space as struct. So far, so good. The problem comes when I try to create the name with extension .cvs for create a new cvs files.

The script I have done so far is:

for i=1:2
path='C:\Program Files\MATLAB\R2010a\toolbox\catool';
filePattern=sprintf('*.00%d',i);
files=dir([path '\' filePattern]);
filesnames{i}=files;
%first_name=filesnames{i}.name;
result{i} = load_ifile(filesnames{1,i}.name,1);

 
    for kk=1:4    
       MFB_5{i,kk}=result{1,i}.(sprintf('AI05_%d',kk)).data';
       MFB_10{i,kk}=result{1,i}.(sprintf('AI10_%d',kk)).data';    
       MFB_50{i,kk}=result{1,i}.(sprintf('AI50_%d',kk)).data';    
       MFB_90{i,kk}=result{1,i}.(sprintf('AI90_%d',kk)).data';
    end
        
  %  MFB_combine={MFB_5;MFB_10;MFB_50;MFB_90};
        

     excel_name{i}=cellstr(filesnames{1,i}.name(1:end-4));
     Filename{i}=strcat(excel_name{1,i},'.cvs');
     
     xlswrite(Filename{1,i},MFB_5{1,i});
    
   % name=Filename{1,1};
    
end

Filename is a cell array with the new names for cvs files. I expected to have two cvs files wih the names contained in Filename (that has been previously obtained from the original files). However, it comes out an error that says:

??? Error using ==> xlswrite at 156

Filename must be a string.

Error in ==> test3 at 23

xlswrite(Filename{1,i},MFB_5{1,i});

I am using Matlab R2010a

Any help or guide it would be really appreciated.

Thanks in advanced.

Best regards

Answer 1

[Jan]

Some comments:

path='C:\Program Files\MATLAB\R2010a\toolbox\catool';

Do not shadow theportant function path by a local variable, because this can cause serious troubles during debugging.

files=dir([path '\' filePattern]);

Prefer fullfile instead of a horizontal concatenation, because it considers e.g. trailing file separators, when the folder is c:\ .

filesnames{i}=files;

This is at least confusing. files is a struct array, most likely a scalar one, so why do you insert it into a cell array? The "...names" part reduces the clarity also, because filesnames does not contains "names". In addition using the name only without a path will lead to unexpected results, if the path is not the current folder. I recommend:

filesnames{i} = fullfile(path, files(1).name);
result{i}     = load_ifile(filesnames{i}, 1);

[folder, file, ext] = fileparts(filesnames{i});
excel_name{i}       = fullfile(folder, file);
Filename{i}         = strcat(excel_name{i}, '.cvs');
xlswrite(Filename{i}, MFB_5{1, i});

Your problem was, that after

excel_name{i}=cellstr(filesnames{1,i}.name(1:end-4));

the variable excel_name is a cell, which contains a cell string. This is equivalent to:

excel_name = {{'FileName.cvs'}};   % TWO curly braces

Note: Your naming scheme is confusing. Mixing singular and plural, joining the terms or separating them with an undersord, upper/lowercase, "filesnames" for something which is not a list of names, but a struct replied by dir. Simplifying the naming scheme will help to avoid such problems as in your case. A cleaner version:

folder = 'C:\Program Files\MATLAB\R2010a\toolbox\catool';
for iFile = 1:2   % smarter than "i" 
  filePattern = sprintf('*.00%d', iFile);
  fileList    = dir(fullfile(folder, filePattern);
  fileName{i} = fullfile(folder, file);
  result{i}   = load_ifile(filesnames{1,i}.name,1);
  for kk = 1:4    
       MFB_5{i,kk}  = result{i}.(sprintf('AI05_%d',kk)).data';
       MFB_10{i,kk} = result{i}.(sprintf('AI10_%d',kk)).data';    
       MFB_50{i,kk} = result{i}.(sprintf('AI50_%d',kk)).data';    
       MFB_90{i,kk} = result{i}.(sprintf('AI90_%d',kk)).data';
  end
  [~, file]    = fileparts(fileName{i});
  excelName{i} = fullfile(folder, [file, '.csv']);
  xlswrite(excelName{i}, MFB_5{i});
end

Do you really need to collect the results in cell arrays? If so, pre-allocate the arrays before the loop:

fileName = cell(1, 2);
result   = cell(1, 2);
... etc.

If you do not use the elements of the cell arrays afterwards, omit the "{i}" indexing.

You are working inside Matlab's installation folder?

path='C:\Program Files\MATLAB\R2010a\toolbox\catool'

This is most likely a bad idea. Prefer to store all used data files, especially if you write into it, to a folder outside the "Program Files" path.

[Santos Romero]

Hello,

It IS WORKING NOW!!!

Thank you for your advice and clarifications. I can say that you know more than I do with matlab. I am really grateful as I have learnt from your explanations and these four-five lines of code I will save me a huge amount of time. THANKS AGAIN!!.

To answer some of your questions, I am saving the elements in cell arrays as I use them afterwards to do some other operations, this is only an small part of the whole script that I am trying to modify in order to automated the process.

I am working inside program files path as I did not manage to make catool works in other way. Maybe I misunderstood the instructions to use the load_ifile function. I will try to make work out of the installation file path.

Last thing, I totally agree that the naming was quite confuse, thanks for the tips. I will try from now on to start with a naming that makes more sense from the beginning instead of doing it afterwards.