How to remove some lines of a file?

I have a File of 8.760 lines. I'll use just the first 744 lines. How can I delete the others?

[Bob Thompson]

What type of file is it? What type of data does it contain?

The general method I would suggest would be to read the file into matlab somehow, and then remove the data you don't need before reprinting the truncated file.

[Bruno Souza]

It is a .txt file. With some numbers Like this:

18.400
19.000
19.000
19.000
18.700

Answer 1

[Akira Agata]

Assuming your file is a text file, you can extract the first 744 lines ans save it like this:

% Full path of the sample text file
filePath = fullfile(matlabroot,'examples','matlab','sonnets.txt');

% Read the file
fid = fopen(filePath,'r');
str = textscan(fid,'%s','Delimiter','\n');
fclose(fid);

% Extract first 744 lines
str2 = str{1}(1:744);

% Save as a text file
fid2 = fopen('test.txt','w');
fprintf(fid2,'%s\n', str2{:});
fclose(fid2);

[Bruno Souza]

It is working. Can I still have the data like this?

18.400
19.000
19.000
19.000
18.700

Because the new data is like that:

18.400 19.000 19.000 19.000 18.700

[Akira Agata]

> Because the new data is like that:

This is because the fprint in my script does not add carriage return ('\r') at the end of the line. To add this, please use the following:

   fprintf(fid2,'%s\r\n', str2{:});

By the way, if your data file contains numbers only, you can use dlmread and dlmwrite and do your task much easier, like:

x = dlmread('yourData.txt');
dlmwrite('test.txt',x(1:744),'newline','pc');

...only 2 lines!