python 多线程threading程序

import threading
import time

# 打印函数a
def printa(a):
    count = 0
    while count < 5:
        time.sleep(2)
        print("线程：%s。

打印：%s。

时间：%s。

" % (threading.current_thread().name, a, time.ctime()))
        count += 1

# 打印函数b
def printb(b):
    count = 0
    while count < 5:
        time.sleep(4)
        print("线程：%s。

打印：%s。

时间：%s。

" % (threading.current_thread().name, b, time.ctime()))
        count += 1

# threading.Thread(target=,args=(),name='')
t1 = threading.Thread(target=printa, args=(10,), name='线程1')
t2 = threading.Thread(target=printb, args=(20,), name='线程2')

t1.start()
t2.start()

t1.join()
t2.join()

print("退出主线程")

import threading
import time

# 打印函数a
def printa(a):
    count = 0
    while count < 5:
        time.sleep(2)
        print("线程：%s。

打印：%s。

时间：%s。

" % (threading.current_thread().name, a, time.ctime()))
        count += 1

# threading.Thread(target=,args=(),name='')
threadList = []
for i in range(3):
    t = threading.Thread(target=printa, args=(i,))
    threadList.append(t)

for t in threadList:
    t.start()

for t in threadList:
    t.join()
    
print("退出主线程")