fopen problem help please

Question

Anton Gubrienko 2021-4-15

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/802611-fopen-problem-help-please

评论： Ankriti Sachan 2021-4-20

In this part of code

disp(filename)
fid=fopen([filename '.hea']);
    disp('debug')

I have error

---WFDB/I0005 ->(its a display filename, i have in WFDB folder files I0005.hea and i0005.mat)

---Error using fopen

---First input must be a file name or a file identifier.

Please, help with fopen) (m2020 mac version)

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Stephen23 2021-4-15

@Anton Gubrienko: please show the complete error message. This means all of the red text.

Walter Roberson 2021-4-15

I suspect that your filename variable is a cell array instead of a character vector or string scalar

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Answer 1

Ankriti Sachan 2021-4-20

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/802611-fopen-problem-help-please#answer_679742

As Walter mentioned, I am also guessing that you are providing a folder name instead of a filename as the input to the fopen function. Please verify the same. Also, you can verify if any other file in the same folder is accessible using fopen.

Also, if you are trying to read the physionet data, please refer to the answer here - https://in.mathworks.com/matlabcentral/answers/528018-how-can-i-create-a-vector-from-one-specific-data-in-552-hea-files-in-matlab.

I hope this answers your query.

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Walter Roberson 2021-4-20

在 MATLAB Online 中打开

First input must be a file name or a file identifier

You do not get that message if you accidentally name a directory instead of a file.

mkdir junk_dir_for_test
[fid, msg] = fopen('junk_dir_for_test');
if fid < 0
    warning('failed to open file because: "%s', msg);
else
    fprintf('fopen of directory worked?\n');
    fclose(fid)
end
Warning: failed to open file because: "Is a directory
[fid, msg] = fopen('junk_does_not_exist_for_test');
if fid < 0
    warning('failed to open file because: "%s', msg);
else
    fprintf('fopen of non-existent file worked?\n');
    fclose(fid)
end
Warning: failed to open file because: "No such file or directory
[fid, msg] = fopen({'junk_does_not_exist_for_test'});
Error using fopen
First input must be a file name or a file identifier.
if fid < 0
    warning('failed to open file named as cell because: "%s', msg);
else
    fprintf('fopen of non-existent named as cell file worked?\n');
    fclose(fid)
end