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Good way to import data file

Asked by Kieran Hazell on 5 May 2015
Latest activity Edited by Kieran Hazell on 6 May 2015
Hey, I need to import a large data file into matlab, but I'm unsure of the best way to do it. I've been experimenting with the fopen and textscan but can't get anything to work correctly. Any help is appreciated.

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2 Answers

Answer by Michael Haderlein on 5 May 2015
Edited by Michael Haderlein on 5 May 2015
 Accepted Answer

If the format doesn't change through the file (such that after 10 s, suddenly also data about whatever appears), you can simply use:
fid=fopen('test.txt');
data=textscan(fid,'%*s%f','delimiter',':');
fclose(fid);
t=data{1}(1:4:end);
gs=data{1}(2:4:end);
gflat=data{1}(4:4:end);
gflong=data{1}(3:4:end);

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Answer by David Sanchez
on 5 May 2015

I'm sure this might be shorter, but I guess it'll be a valid solution for you:
fid = fopen('your_file_name_here.txt');
my_file = textscan(fid, '%s', 'delimiter', '\n');
my_file = my_file{1};
fclose(fid)
% now you have a cell array (my_file) with each line of your *.txt in a different
% cell
% you can extract the values like this:
L = length(my_file); % number of lines in your file
my_data = zeros(L,1); % initialization of matrix to hold your data
for k = 1:L % loop along each line
str_value = textscan(my_file{k}, '%s %s', 'delimiter', ':' );
my_data(k) = str2double(cell2mat(str_value{1,2}));
end
I guess you can figure out how to assign every four values to each variable

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