gevent 實現多工：

import gevent

# 遇到延時就切換任務
def f1(n):
    for i in range(n):
        print(gevent.getcurrent(), i)
        gevent.sleep(0.5) # 必須用自己的延時，不能用time模組的延時
def f2(n):
    for i in range(n):
        print(gevent.getcurrent(), i)
        gevent.sleep(0.5)

def f3(n):
    for i in range(n):
        
 
print(gevent.getcurrent(), i)
        gevent.sleep(0.5)

g1 = gevent.spawn(f1, 5) # grenlet 物件
g2 = gevent.spawn(f2, 5)
g3 = gevent.spawn(f3, 5)
g1.join() # 堵塞，+ 延時，切換
g2.join()
g3.join()

　　結果：

 1 D:\python3.7\python.exe E:/code_pycharm/test_in_class/tt13.py
 2 <Greenlet "Greenlet-0" at 0x29a36a8: f1(5)> 0
 
 3 <Greenlet "Greenlet-1" at 0x29a37b8: f2(5)> 0
 4 <Greenlet "Greenlet-2" at 0x29a38c8: f3(5)> 0
 5 <Greenlet "Greenlet-0" at 0x29a36a8: f1(5)> 1
 6 <Greenlet "Greenlet-1" at 0x29a37b8: f2(5)> 1
 7 <Greenlet "Greenlet-2" at 0x29a38c8: f3(5)> 1
 8 <Greenlet "Greenlet-0" at 0x29a36a8: f1(5)> 2
 9
 
 <Greenlet "Greenlet-1" at 0x29a37b8: f2(5)> 2
10 <Greenlet "Greenlet-2" at 0x29a38c8: f3(5)> 2
11 <Greenlet "Greenlet-0" at 0x29a36a8: f1(5)> 3
12 <Greenlet "Greenlet-1" at 0x29a37b8: f2(5)> 3
13 <Greenlet "Greenlet-2" at 0x29a38c8: f3(5)> 3
14 <Greenlet "Greenlet-0" at 0x29a36a8: f1(5)> 4
15 <Greenlet "Greenlet-1" at 0x29a37b8: f2(5)> 4
16 <Greenlet "Greenlet-2" at 0x29a38c8: f3(5)> 4
17 
18 Process finished with exit code 0

使用猴子補丁，可以不用把所有耗時的，阻塞的用gevent裡的代替，該怎麼寫就怎麼寫。

如：time.sleep()的使用

 1 import gevent
 2 import time
 3 from  gevent import monkey
 4 
 5 monkey.patch_all()
 6 
 7 # 遇到延時就切換任務
 8 def f1(n):
 9     for i in range(n):
10         print(gevent.getcurrent(), i)
11         # gevent.sleep(0.5) # 必須用自己的延時，不能用time模組的延時
12         time.sleep(0.5)
13         
14 def f2(n):
15     for i in range(n):
16         print(gevent.getcurrent(), i)
17         gevent.sleep(0.5)
18 
19 def f3(n):
20     for i in range(n):
21         print(gevent.getcurrent(), i)
22         gevent.sleep(0.5)
23 
24 g1 = gevent.spawn(f1, 5) # grenlet 物件
25 g2 = gevent.spawn(f2, 5)
26 g3 = gevent.spawn(f3, 5)
27 g1.join() # 堵塞，+ 延時，切換
28 g2.join()
29 g3.join()

結果：

 1 D:\python3.7\python.exe E:/code_pycharm/test_in_class/tt13.py
 2 <Greenlet "Greenlet-0" at 0x3603268: f1(5)> 0
 3 <Greenlet "Greenlet-1" at 0x3603598: f2(5)> 0
 4 <Greenlet "Greenlet-2" at 0x3603488: f3(5)> 0
 5 <Greenlet "Greenlet-0" at 0x3603268: f1(5)> 1
 6 <Greenlet "Greenlet-1" at 0x3603598: f2(5)> 1
 7 <Greenlet "Greenlet-2" at 0x3603488: f3(5)> 1
 8 <Greenlet "Greenlet-0" at 0x3603268: f1(5)> 2
 9 <Greenlet "Greenlet-1" at 0x3603598: f2(5)> 2
10 <Greenlet "Greenlet-2" at 0x3603488: f3(5)> 2
11 <Greenlet "Greenlet-0" at 0x3603268: f1(5)> 3
12 <Greenlet "Greenlet-1" at 0x3603598: f2(5)> 3
13 <Greenlet "Greenlet-2" at 0x3603488: f3(5)> 3
14 <Greenlet "Greenlet-0" at 0x3603268: f1(5)> 4
15 <Greenlet "Greenlet-1" at 0x3603598: f2(5)> 4
16 <Greenlet "Greenlet-2" at 0x3603488: f3(5)> 4
17 
18 Process finished with exit code 0

用gevet.joinall 

 1 import gevent
 2 import time
 3 from  gevent import monkey
 4 
 5 monkey.patch_all()
 6 
 7 # 遇到延時就切換任務
 8 def f1(n):
 9     for i in range(n):
10         print(gevent.getcurrent(), i)
11         # gevent.sleep(0.5) # 必須用自己的延時，不能用time模組的延時
12         time.sleep(0.5)
13 
14 def f2(n):
15     for i in range(n):
16         print(gevent.getcurrent(), i)
17         gevent.sleep(0.5)
18 
19 def f3(n):
20     for i in range(n):
21         print(gevent.getcurrent(), i)
22         gevent.sleep(0.5)
23 
24 gevent.joinall(
25     gevent.spawn(f1, 5),
26     gevent.spawn(f2, 5),
27     gevent.spawn(f3, 5)
28 
29  )