Error using fscanf Invalid file identifier.

error at the line 63 of the attached code.

I want to read the data files and make a coupling file. sample data file and the code has been attached to the thread.

Please check and give me an answer for the following error.

The section of the code which is giving the error has been included.

%read files into 3 Dim variable: data
% Dim 1 - station number
% Dim 2 - 1:3 is eta, u, v
% Dim 3 - time steps
for numm = 1:nsta
    FILE1 = fopen(sprintf('D:\Mejena_Case\FUNWAVE_Simulation\mejena_tsunami\work\output1\sta_%04d',numm),'r');
    data1 = fscanf(FILE1,'%f',[4 Inf]);
    sides(numm,:,start1:stop1) = data1([4 3 2],start1:stop1);
    fclose(FILE1);
    disp(sprintf('File %d has been read...',numm))
end
disp('All files read')

[Stephen23]

WARNING:

Both the question and the accepted answer have the same problem: they use escape characters in the SPRINTF format string without considering what effect they have. Depending on which character is escaped, this may either generate a (special) character or give a warning and not return any character, e.g.:

sprintf('\M')

Warning: Escaped character '\M' is not valid. See 'doc sprintf' for supported special characters.

ans =

  1×0 empty char array

The robust solution is to NOT place file separator characters in the format string, e.g.:

P = 'D:\Mejena_Case\FUNWAVE_Simulation\mejena_tsunami\work\output1';
F = fullfile(P,sprintf('sta_%04d.txt',7))

F = 'D:\Mejena_Case\FUNWAVE_Simulation\mejena_tsunami\work\output1/sta_0007.txt'

[幸一]

i tried this step and it is not working.

I extremely sorry for disturbing to you all.

Answer 1

[VINAYAK LUHA]

Change line 62 with

FILE1 = fopen(sprintf('D:\\Mejena_Case\\FUNWAVE_Simulation\\mejena_tsunami\\work\\output1\\sta_%04d.txt',numm),'r');

[幸一]

thank you very much for your kind reply.

I will check it and let you know.

[幸一]

these are not text files.

output save like 'sta_0001' no file extension.

Your suggestion is not working.

[幸一]

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

Error in couplerFNW_NHW (line 63) data1 = fscanf(FILE1,'%f',[4 Inf]);

still same error

[VINAYAK LUHA]

Hi Again.

Apparently your "fopen" function is unable to open the said file, either the path is incorrect or you don't have the read permissions. Try this out once and let me know if it doesn't work.

FILE1 = fopen(sprintf('D:\\Mejena_Case\\FUNWAVE_Simulation\\mejena_tsunami\\work\\output1\\sta_%04d',numm),'r');

[幸一]

Hello,

sorry for disturbing. I once tried your suggesstion again. now code has verified about the number of files. but again following error appeared and any output file did not make.

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

Error in couplerFNW_NHW (line 63)

data1 = fscanf(FILE1,'%f',[4 Inf]);

[Walter Roberson]

filename = "D:\Mejena_Case\FUNWAVE_Simulation\mejena_tsunami\work\output1\sta_" + compose('%04d', numm);
[FILE1, msg] = fopen(filename,'r');
if FILE1 < 0
    error('failed to open file "%s" because "%s"', filename, msg);
end

[幸一]

Thank you very much sir.

I will make the suggessted changes and look what will happen.

[幸一]

i checked then again giving an error like this.

Error using couplerFNW_NHW (line 67) failed to open file

"D:\Mejena_Case\FUNWAVE_Simulation\mejena_tsunami\work\output_mejena1\sta_0049"

because "No such file or directory"

I uploaded all the files to this thread. please check whether giving an output according to the code.

[Stephen23]

@幸一: your data file has the file extension .txt

Neither your code nor the code given by @VINAYAK LUHA specify the file extension (so the filename you generate does not exist). If your file has a file extension then you need to specify it, e.g. as I showed you here:

https://www.mathworks.com/matlabcentral/answers/2068366-error-using-fscanf-invalid-file-identifier#comment_3025246

[幸一]

dear sir,

data file does not have a file extension. I attached the xipped folder for this thread.

please check if possible and let me know a solution.

I tried all the suggesstions raised and nothig is working right now.

[Stephen23]

@幸一: please show the complete output of these commands:

S = dir('D:\Mejena_Case\FUNWAVE_Simulation\mejena_tsunami\work\output1\sta*')
{S.names}
[S.isdir]

[幸一]

not working the above command.

Following is the error message

Unrecognized field name "names". Error in untitled (line 2)

{S.names};

[Walter Roberson]

Try

S = dir('D:\Mejena_Case\FUNWAVE_Simulation\mejena_tsunami\work\output1\sta*')
{S.name}
[S.isdir]

[幸一]

hello sir,

this is the output of the above given code

ans =

0×0 empty cell array

ans =

[]

[Walter Roberson]

Your files are not in D:\Mejena_Case\FUNWAVE_Simulation\mejena_tsunami\work\output1

Note: the zip result shows the files as being in a folder named stationResults but that folder is not part of the path .

[幸一]

please sory sir. I made a mistake. this is the output

ans =

1×48 cell array

Columns 1 through 6

{'sta_0001'} {'sta_0002'} {'sta_0003'} {'sta_0004'} {'sta_0005'} {'sta_0006'}

Columns 7 through 12

{'sta_0007'} {'sta_0008'} {'sta_0009'} {'sta_0010'} {'sta_0011'} {'sta_0012'}

Columns 13 through 18

{'sta_0013'} {'sta_0014'} {'sta_0015'} {'sta_0016'} {'sta_0017'} {'sta_0018'}

Columns 19 through 24

{'sta_0019'} {'sta_0020'} {'sta_0021'} {'sta_0022'} {'sta_0023'} {'sta_0024'}

Columns 25 through 30

{'sta_0025'} {'sta_0026'} {'sta_0027'} {'sta_0028'} {'sta_0029'} {'sta_0030'}

Columns 31 through 36

{'sta_0031'} {'sta_0032'} {'sta_0033'} {'sta_0034'} {'sta_0035'} {'sta_0036'}

Columns 37 through 42

{'sta_0037'} {'sta_0038'} {'sta_0039'} {'sta_0040'} {'sta_0041'} {'sta_0042'}

Columns 43 through 48

{'sta_0043'} {'sta_0044'} {'sta_0045'} {'sta_0046'} {'sta_0047'} {'sta_0048'}

ans =

1×48 logical array

Columns 1 through 26

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Columns 27 through 48

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

[Walter Roberson]

The code has

neast = 0;
nwest = 131;
nsouth = 0;
nnorth = 0;

nsta = neast+nwest+nsouth+nnorth;

so nsta is 131

The code has

for numm = 1:nsta
    FILE1 = fopen(sprintf('D:\Mejena_Case\FUNWAVE_Simulation\mejena_tsunami\work\output1\sta_%04d',numm),'r');

so the code will try to open up to sta_0131

However, your directory only has up to sta_0048 stored in it.

[幸一]

hello sir.

thank you very much for your kind reply.

I will recheck the code again.