Asyncio.gather vs asyncio.wait

asyncio.gather and asyncio.wait seem to have similar uses: I have a bunch of async things that I want to execute/wait for (not necessarily waiting for one to finish before the next one starts). They use a different syntax, and differ in some details, but it seems very un-pythonic to me to have 2 functions that have such a huge overlap in functionality. What am I missing?

Although similar in general cases ("run and get results for many tasks"), each function has some specific functionality for other cases:

asyncio.gather()

Returns a Future instance, allowing high level grouping of tasks:

    import asyncio
    from pprint import pprint

    import random


    async def coro(tag):
        print(">", tag)
        await asyncio.sleep(random.uniform(1, 3))
        print("<", tag)
        return tag


    loop = asyncio.get_event_loop()

    group1 = asyncio.gather(*[coro("group 1.{}".format(i)) for i in range(1, 6)])
    group2 = asyncio.gather(*[coro("group 2.{}".format(i)) for i in range(1, 4)])
    group3 = asyncio.gather(*[coro("group 3.{}".format(i)) for i in range(1, 10)])

    all_groups = asyncio.gather(group1, group2, group3)

    results = loop.run_until_complete(all_groups)

    loop.close()

    pprint(results)

All tasks in a group can be cancelled by calling group2.cancel() or even all_groups.cancel(). See also .gather(..., return_exceptions=True),

asyncio.wait()

Supports waiting to be stopped after the first task is done, or after a specified timeout, allowing lower level precision of operations:

    import asyncio
    import random


    async def coro(tag):
        print(">", tag)
        await asyncio.sleep(random.uniform(0.5, 5))
        print("<", tag)
        return tag


    loop = asyncio.get_event_loop()

    tasks = [coro(i) for i in range(1, 11)]

    print("Get first result:")
    finished, unfinished = loop.run_until_complete(
        asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED))

    for task in finished:
        print(task.result())
    print("unfinished:", len(unfinished))

    print("Get more results in 2 seconds:")
    finished2, unfinished2 = loop.run_until_complete(
        asyncio.wait(unfinished, timeout=2))

    for task in finished2:
        print(task.result())
    print("unfinished2:", len(unfinished2))

    print("Get all other results:")
    finished3, unfinished3 = loop.run_until_complete(asyncio.wait(unfinished2))

    for task in finished3:
        print(task.result())

    loop.close()

From: stackoverflow.com/q/42231161