Problem with fscanf command in creating .txt file

Question

Ivan Mich 2021-3-2

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/760201-problem-with-fscanf-command-in-creating-txt-file

编辑： Jan 2021-3-2

Result_new.txt

I would like to create an output .txt file. This .txt file is a result of merging vertically multiple .txt files with the same suffix.

I have this script but I have problem with fscanf.

fid_p = fopen('final.txt','w'); % writing file id
x= dir ('*new.txt');
for i =1:length(x)
    filename1 = ['*new.txt'];%filename
    fid_t=fopen(filename1,'r');%open it and pass id to fscanf (reading file id)
    data = fscanf(fid_t,'%c');%read data
    fprintf(fid_p,'%c',data);%print data in File_all
    fclose(fid_t);% close reading file id
    fprintf(fid_p,'\n');%add newline
end
fclose(fid_p); %close writing file id

I am importing one example of my files (Imagine that all my files have 3 columns, and the first include strings/characters)

Could you please help me?

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Jan 2021-3-2

"I have this script but I have problem with fscanf." - If you mention, what the problem is, we can suggest an improvement.

Ivan Mich 2021-3-2

command window shows me:

Error using fscanf

Invalid file identifier. Use fopen to generate a valid file identifier.

Error in code (line 32)

data = fscanf(fid_t,'%c');%read data

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Answer 1

Jan 2021-3-2

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/760201-problem-with-fscanf-command-in-creating-txt-file#answer_636966

编辑：Jan 2021-3-2

在 MATLAB Online 中打开

    filename1 = ['*new.txt'];%filename
    fid_t=fopen(filename1,'r')    

This cannot work: '*new.txt' is not a valid file name, because the * is not allowed.

fid_p = fopen('final.txt','w'); % writing file id
if fid_p < 0, error('Cannot open file for writing.'); end
x = dir ('*new.txt');
for i = 1:length(x)
    filename1 = x(i).name;  %filename
    fid_t = fopen(filename1, 'r');%open it and pass id to fscanf (reading file id)
    if fid_t < 0, error('Cannot open file for reading.'); end
    data = fread(fid_t, inf, '*char');%read data
    fwrite(fid_p, data, 'char');%print data in File_all
    fclose(fid_t);% close reading file id
    fprintf(fid_p,'\n');%add newline
end
fclose(fid_p); %close writing file id

This take the file name from the list of files in x. In addition it uses FREAD and FRWITE, because it is faster to access the files in binary mode.

Never use FOPEN without testing the success.

Working with relative paths is less reliable than absolute path names:

Folder = 'C:\Your\Folder';
FileList  = dir (fullfile(Folder, '*new.txt'));
for iFile = 1:numel(FileList)
    FileName = fullfile(Folder, FileList(iFile).name);
    ...
end