1 # -*- coding:utf-8 -*-
 2 # Author:Sure Feng
 3 
 4 
 5 import threading
 6 import time
 7 
 8 
 9 num = 0
10 
11 
12 def sing():
13     # 線程間共享全局變量，可能導致數據混亂
14     global num
15     for i in range(5000):
16         num += 1
17         print("--第【%d】次sing----" % num)
18         # time.sleep(0.1)
19 
20
 
 
21 class Dance(threading.Thread):
22     def run(self):
23         global num
24         for i in range(5000):
25             num += 1
26             print("---第【%d】次dance---" % num)
27             # time.sleep(0.1)
28 
29 
30 def main():
31     # 調用線程的第一種方法
32     t1 = threading.Thread(target=sing)
33
 
     # 調用線程的第二種方法
34     t2 = Dance()
35     t1.start()
36     t2.start()
37 
38     while True:
39         # 查看當前線程數量
40         threading_num = len(threading._enumerate())
41         print("當前的線程數量為%d" % threading_num)
42         if threading_num <= 1:
43             break
44 
45         # time.sleep(0.3)
 

46 
47 if __name__ == "__main__":
48     main()

線程（調用的兩種方法、全局變量共享、線程數量）