为什么 enumerate() 在这里没有按预期工作？

Question

I've trying to use enumerate to do something every nth iteration. In the below example I'm using a chunked iterable. The original iterable is a list of 1000000 URLs and the generator, it's broken into 1000 chunks. Now if I use:

if count % 2 == 0:

it works as intended ie every second chunk, it prints out abc . However if I try to use:

if count % 1 == 0:

instead of abc being printed out after every chunk completes, it prints abc after every individual item in the original list completes. In other words, I get a million abc outputs instead of 1000. What am I doing wrong?

def chunk_iterable(iterable, chunk_size):
    chunk = []
    for item in iterable:
        chunk.append(item)
        if len(chunk) == chunk_size:
            yield chunk
            chunk = []
    if chunk:
        yield chunk


async def make_async_requests(directory, file, urls):
    sem = asyncio.BoundedSemaphore(50)
    chunk_size = 10000
    async with aiohttp.ClientSession() as session:
        for count, chunk in tqdm.tqdm(enumerate(chunk_iterable(urls, chunk_size)), total=len(urls)/chunk_size)):
            await tqdm.asyncio.tqdm.gather(*[write_to_file(url, sem, session) for url in chunk])
            if count % 1 == 0:
                print("abc")
                continue

Answer 1

The problem here isn't enumerate() , it's the use of the modulo operator here:

if count % 1 == 0:

This condition will always be true because the modulo of 1 will always be a zero, if you want a thousand outputs instead of a million (if it's an exact million) try:

if count % 1000 == 0: