import time
def test1():
 while True:
  print("--1--")
  time.sleep(0.5)
  yield None
def test2():
 while True:
  print("--2--")
  time.sleep(0.5)
  yield None
if __name__ == "__main__":
  t1 = test1()
  t2 = test2()
  while True:
    next(t1)
    next(t2)

from greenlet import greenlet
import time
def test1():
 while True:
  print("---A---")
  gr2.switch()
  time.sleep(0.5)
def test2():
 while True:
  print("---b---")
  gr1.switch()
  time.sleep(0.5)
gr1 = greenlet(test1)
gr2 = greenlet(test2)
gr1.switch()

import gevent
import time
from gevent import monkey
# 打补丁，不需要改原来的耗时操作，否则是要使用gevent提供的模块
monkey.patch_all()
def f(n):
 for i in range(n):
  print(gevent.getcurrent(), i)
  # 使用gevent提供的耗时模块
  # gevent.sleep(0.5)
  time.sleep(0.5)
g1 = gevent.spawn(f, 5)
g2 = gevent.spawn(f, 5)
g3 = gevent.spawn(f, 5)
# g1.join()
# g2.join()
# g3.join()
# 一次性添加全部的任务
gevent.joinall([g1,g2,g3])