Hi! Could somebody tell me why few days ago this code worked and now I tried it again and gives me this error? Thank you!

fmt=['PG10 ' repmat('%f ',1,8)];
fid=fopen('sp3data.txt');
PG10=[];
while ~feof(fid)
  l=fgetl(fid);        % read a record
  if strfind(l,'PG10')
    PG10=[PG10; cell2mat(textscan(l,fmt,'collectoutput',1))];
  end
end
fclose(fid);

Error using feof
Invalid file identifier. Use fopen to generate a valid file identifier.

Answer 1

[Stephen23]

Replace the fopen line with this:

[fid,msg] = fopen('sp3data.txt');
assert(fid>=3,msg)

And then read the displayed message. Most likely fopen cannot open the file because there is no such file in the specified location.

[gblmtc]

Thank you!