def simple_gen():
	yield 'hello'
	yield 'world'

gen = simple_gen()
print(type(gen))  # 'generator' object
print(next(gen))  # 'hello'
print(next(gen))  # 'world'

def coro():
	hello = yield 'hello'  # yield 關(guān)鍵字在 = 右邊作為表達式，可以被 send 值
	yield hello

c = coro()
# 輸出 'hello', 這里調(diào)用 next 產(chǎn)出第一個值 'hello'，之后函數(shù)暫停
print(next(c))
# 再次調(diào)用  send 發(fā)送值，此時 hello 變量賦值為 'world'，然后 yield 產(chǎn)出 hello 變量的值 'world'
print(c.send('world'))
# 之后協(xié)程結(jié)束，后續(xù)再 send 值會拋出異常 StopIteration

from functools import wraps

def coroutine(func):  # 這樣就不用每次都用 send(None) 啟動了
	“”“裝飾器：向前執(zhí)行到一個 `yield` 表達式，預(yù)激 `func` ”“”
	@wrops(func)
	def primer(*args, **kwargs):   # 1
		gen = func(*args, **kwargs)  # 2
		next(gen)  # 3
		return gen  # 4
	return primer

import asyncio
import datetime
import random

async def display_date(num, loop):
	end_time = loop.time() + 50.0
	while True:
		print('Loop: {} Time: {}'.format(num, datetime.datetime.now())
		if (loop.time() + 1.0) >= end_time:
			break
		await asyncio.sleep(random.randint(0, 5))

loop = asyncio.get_event_loop()
asyncio.ensure_future(display_date(1, loop))
asyncio.ensure_future(display_date(2, loop))
loop.run_forever()