I've got a multi-GB file that has elements in 4 lines, and I would like to have every 4 lines randomized in another file, this is, keeping each four lines grouped and randomize those sets. Is there an easy way to do that?
If you're using a reasonable new linux/unix distribution,
This is in Python. I'm sure someone will post a Perl answer too. ;-)
#!/usr/bin/python import random #Change these to the desired files infile = "/path/to/input/file" outfile = "/path/to/output/file" fh = file(infile) contents = fh.readlines() fh.close() chunked = [contents[i:i+4] for i in xrange(0, len(contents), 4)] random.shuffle(chunked) fh = file(outfile, 'w') for chunk in chunked: for line in chunk: fh.write(line) fh.close()
IANA Programmer so somebody could probably improve this, but I tested it and it works just fine.