#!/usr/bin/env python3

import sys
import random

if len(sys.argv) < 2:
    print('Usage:<filename> <k> [nfold = 5]')
    exit(0)

random.seed(10)

k = int(sys.argv[2])
if len(sys.argv) > 3:
    nfold = int(sys.argv[3])
else:
    nfold = 5

fi = open(sys.argv[1], 'r')
ftr = open(sys.argv[1] + '.train', 'w')
fte = open(sys.argv[1] + '.test', 'w')
for l in fi:
    if random.randint(1, nfold) == k:
        fte.write(l)
    else:
        ftr.write(l)

fi.close()
ftr.close()
fte.close()