Read a file asynchronously using aiofiles, remove empty lines from a file

aiofiles_test.py

# python3 aiofiles_test.ty some_file_with_newlines

import sys
import asyncio
import aiofiles


async def read(filename):
    async with aiofiles.open(filename, mode='r') as f:
        return await f.read()

async def dump(filename, contents): # contents is an iterable
    async with aiofiles.open(filename, mode='w') as old_f:
        await old_f.write("\n".join(contents))
        await old_f.flush()

    
filename = sys.argv[1]
loop = asyncio.get_event_loop()
contents = loop.run_until_complete(read(filename))
contents = list(filter(lambda x: bool(x.strip()), contents.splitlines()))
loop.run_until_complete(dump(filename, contents))

print(contents)