Hello,
I am looking for a method to "shuffle" the lines of a large file.
I have a corpus of sorted and "uniqed" English sentences that has been produced with (1):
(1) sort corpus | uniq > corpus.uniq
corpus.uniq is 80G large. The fact that every sentence appears only once in corpus.uniq plays an important role for the processes I use to involve my corpus in. Yet, the alphabetical order is an unwanted side effect of (1): Very often, I do not want (or rather, I do not have the computational capacities) to apply a program to all of corpus.uniq. Yet, any series of lines of corpus.uniq is obviously a very lopsided set of English sentences.
So, it would be very useful to do one of the following things:
- produce corpus.uniq in a such a way that it is not sorted in any way - shuffle corpus.uniq > corpus.uniq.shuffled
Unfortunately, none of the machines that I may use has 80G RAM. So, using a dictionary will not help.
There was a thread a while ago about choosing random lines from a file without reading the whole file into memory. Would that help? Instead of shuffling the file, shuffle the users. I can't find the thread though...
Kent -- http://mail.python.org/mailman/listinfo/python-list
