asyncio.gather schedules multiple coroutines as tasks and waits for all of them to finish. Their results stay in input order, even when completion order differs. Concurrent execution can reduce total runtime: tasks taking about five and three seconds finish in about five seconds together, rather than eight seconds sequentially. section 7.5.1
Listing 7.17 asyncio example
import asyncio
import time
async def func1():
print("Start func1")
await asyncio.sleep(5)
print("End func1")
return "func1 complete"
async def func2():
print("Start func2")
await asyncio.sleep(3)
print("End func2")
return "func2 complete"
async def main():
start_time = time.time()
co_routines = asyncio.gather(func1(), func2())
a, b = await co_routines
print(a, b)
end_time = time.time()
print("time", end_time-start_time)
asyncio.run(main())
Runs two coroutines with different sleep durations, awaits their results, and measures elapsed time. section 7.5.1
