How can I read part of file and write the rest to another file?

Question

I have multiple large csv file. How can I read part of each file and write 10% of the data/rows to another file?

Answer 1

This works for me:

with open("in.csv") as infile, open("out.csv", "w") as outfile:
    outcsv = csv.writer(outfile)
    for i, row in enumerate(csv.reader(infile)):
        if not i % 10:
            outcsv.writerow(row)