Random access file writing

multi_write.py

import os
import time
import random

FN = 'my-tmp-file.txt'
SIZE = (2 ** 10)  # 1K


if not os.path.exists(FN):
    with open(FN, 'wb') as f:
        # f.truncate(SIZE - 1)
        # # f.write('start')
        f.seek(SIZE - 1)
        f.write('\0')

print open(FN, 'rb').read()

while True:
    index = random.randint(0, SIZE)
    print index
    with open(FN, 'r+b') as f:
        f.seek(index)
        f.write('-{}-'.format(index))
    print open(FN, 'rb').read(SIZE - 1)
    time.sleep(0.1)