MATLAB: How to split a sing column .txt file by line

bydividefilehelplineMATLABsplittxt

Hey Guys,
How would I split a .txt file into smaller files by the number of lines? This was simple to do in linux, but I can't seem to do it here.
An example of a file is attached (testv2.txt)
EDIT: The .txt files I'm working with are very large, and I need to split them into files with 72,000,000 lines. I can't split the files by size, because for some reason some files are different sizes, and the script I'm using tells time by using the # of lines.
Thanks for the help guys!

Best Answer

Again, I'd suggest there's no need to actually create multiple text files to do this...several options exist in MATLAB; the simplest is probably to just process the file in chunks of whatever size you wish and calculate statistics or do whatever on each section...something like
fid=fopen('yourfile.txt','r');
NperSet=72E6;                                          % set number elements to read per section
ix=0;                                                  % initialize group index counter
while ~feof(fid)                                       % go thru the file until run out of data
  ix=ix+1;                                             % increment counter
  data=cell2mat(textscan(fid,'%\t%f',NperSet));        % read the data chunk of set size, skip \t
  stats(ix,:)=[mean(data) std(data) ...];              % compute, save the stats of interest
  ...                                                  % do whatever else needed w/ this dataset here
end
You'll want to preallocate the stats array to some reasonable approximation of the size expected and check for overflow, but that's the basic idea...simpler than creating and having to traverse thru a bunch of files to simply process in sequence.
The alternative is to use tall arrays or memmapfile or other of the features TMW has provided for large datasets. See <Large-files-and-big-data link>
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