Thread Subject:

error invalid identifier

When I start my program i get an error message saying ???
Error using ==> textscan
Invalid file identifier. Use fopen to generate a valid file identifier.

Error in ==> abc at 23
    for i=1:18 hdr=textscan(fid,'%s %*[^\n]',1); end
for the program

function spec = abc(filelist);

filelist='add.txt';
fl = importdata(filelist);

apfile = size(fl,1);
%fid = fopen(file);

bcc = 1024;

spec = zeros(apfile, bcc);

for iFile = 1:nFile
    
    fid = fopen(fl{apfile});
    
       for i=1:18 hdr=textscan(fid,'%s %*[^\n]',1); end
    
    x=textscan(fid,'%d%d','delimiter',',,');
    x = x{:,1};
    
    x = reshape(x,2,bcc);
    spec(apFile,:) = x(2,:);
    
    fclose(fid);
    
end

"Leah " <strawberriesncream8148@yahoo.com> wrote in message
news:jtfgqo$eg7$1@newscl01ah.mathworks.com...
> When I start my program i get an error message saying ??? Error using ==>
> textscan
> Invalid file identifier. Use fopen to generate a valid file identifier.
>
> Error in ==> abc at 23
> for i=1:18 hdr=textscan(fid,'%s %*[^\n]',1); end
> for the program

*snip*

> fid = fopen(fl{apfile});

Call FOPEN with two outputs. Before using fid, check if it's -1:

http://www.mathworks.com/help/techdoc/ref/fopen.html

"An integer that identifies the file for all subsequent low-level file I/O
operations. If fopen cannot open the file, fileID is -1."

If fid is -1, display the second output:

"A system-dependent error message when fopen cannot open the specified file.
Otherwise, an empty string."

That should help you determine why the attempt to open the file failed.

Then modify your code and/or your system appropriately for your application.

*snip*

--
Steve Lord
slord@mathworks.com
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