textscan error only in loop: "Invalid file identifier. Use fopen to generate a valid file identifier"

1 次查看（过去 30 天）
Cakil
Cakil 2022-4-21
评论： Cakil 2022-4-21
Hi,
I am receiving textscan error when I create a loop to process and write my files. If I run each file individually without a loop, it works without any problem. If anyone knows what will be the reason of it?
"Error using textscan.Invalid file identifier. Use fopen to generate a valid file identifier."
[fname,pname] = uigetfile("MultiSelect","on",'*.dat')
fname=[pname, fname];
if isequal(fname,0)
disp('User selected Cancel');
else
disp(['User selected ', fullfile(pname, fname)]);
end
for k = 1 : length(fname)
fprintf('Now reading file %s\n', fname{k});
fid=fopen(fname{k},'r');
F=textscan(fid,'%f','HeaderLines',17);
Temp=F{1,1}
T_out = timetable(datetime(2018,1,17,0,0,10*(0:size(Temp,1)-1)'),Temp);
time_array=datetime("29-May-2018 00:00:00", "InputFormat","dd-MMM-uuuu HH:mm:ss")
summerstart=find(T_out.Time=="29-May-2018 00:00:00")
Tsummer=T_out([summerstart]:end,:)
[filepath,name,ext] = fileparts(fname)
writetimetable(Tsummer,[name 'r.csv'])
end
Thanks a lot!

请先登录，再回答此问题。

采纳的回答

Stephen23
Stephen23 2022-4-21
编辑：Stephen23 2022-4-21
This will not work as you require:
fname=[pname, fname];
Instead you should use FULLFILE, to correctly handle the file separator character, for example:
[fnc,fpt] = uigetfile("MultiSelect","on",'*.dat');
if isequal(fnc,0)
return
end
for k = 1:numel(fnc)
fprintf('Now reading file %s\n', fnc{k});
fnm = fullfile(fpt,fnc{k}); % better to use FULLFILE
fid = fopen(fnm,'r');
tmp = textscan(fid,'%f','HeaderLines',17);
fclose(fid); % you need to FCLOSE every file
.. etc
end

更多回答（1 个）

Jonas
Jonas 2022-4-21
编辑：Jonas 2022-4-21
use fclose(fid) at the end of the for loop
sometimes, if using a script a file remains open and you may not have the identifier anymore. in this case use fclose('all')

类别

在 Help Center 和 File Exchange 中查找有关 Text Files 的更多信息

标签

产品


版本

R2021a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by