python之系统编程 --线程

from threading import Thread
import time

#1. 如果多个线程执行的都是同一个函数的话，各自之间不会有影响，各是个的
def test():
    print("----昨晚喝多了，下次少喝点---")
    time.sleep(1)


for i in range(5):
    t = Thread(target=test)
    t.start()

import threading
import time

class MyThread(threading.Thread):
    def run(self):
        for i in range(3):
            time.sleep(1)
            msg = "I‘m "+self.name+‘ @ ‘+str(i) #name属性中保存的是当前线程的名字
            print(msg)


if __name__ == ‘__main__‘:
    t = MyThread()
    t.start()

[root@master process]# python3 09-thread.py 
I‘m Thread-1 @ 0
I‘m Thread-1 @ 1
I‘m Thread-1 @ 2

from threading import Thread
import time

#线程之间共享全局变量
g_num = 100

def work1():
    global g_num
    for i in range(3):
        g_num += 1

    print("----in work1, g_num is %d---"%g_num)


def work2():
    global g_num
    print("----in work2, g_num is %d---"%g_num)


print("---线程创建之前g_num is %d---"%g_num)

t1 = Thread(target=work1)
t1.start()

#延时一会，保证t1线程中的事情做完
time.sleep(1)

t2 = Thread(target=work2)
t2.start()

from threading import Thread
import time

g_num = 0

def test1():
    global g_num
    for i in range(1000000):
        g_num += 1

    print("---test1---g_num=%d"%g_num)

def test2():
    global g_num
    for i in range(1000000):
        g_num += 1

    print("---test2---g_num=%d"%g_num)


p1 = Thread(target=test1)
p1.start()

#time.sleep(3) #取消屏蔽之后 再次运行程序，结果会不一样，，，为啥呢？

p2 = Thread(target=test2)
p2.start()

print("---g_num=%d---"%g_num)

from threading import Thread
import time

def work1(nums):
    nums.append(44)
    print("----in work1---",nums)


def work2(nums):
    #延时一会，保证t1线程中的事情做完
    time.sleep(1)
    print("----in work2---",nums)

g_nums = [11,22,33]

t1 = Thread(target=work1, args=(g_nums,))
t1.start()

t2 = Thread(target=work2, args=(g_nums,))
t2.start()

from threading import Thread
import time

g_num = 0
g_flag = 1

def test1():
    global g_num
    global g_flag
    if g_flag == 1:
        for i in range(1000000):
            g_num += 1

        g_flag = 0

    print("---test1---g_num=%d"%g_num)

def test2():
    global g_num
    #轮询
    while True:
        if g_flag != 1:
            for i in range(1000000):
                g_num += 1
            break

    print("---test2---g_num=%d"%g_num)


p1 = Thread(target=test1)
p1.start()

#time.sleep(3) #取消屏蔽之后 再次运行程序，结果会不一样，，，为啥呢？

p2 = Thread(target=test2)
p2.start()

print("---g_num=%d---"%g_num)

from threading import Thread, Lock
import time

g_num = 0

def test1():
    global g_num
    #这个线程和ｔｅｓｔ2线程都在抢着　对这个锁　进行上锁，如果有１方成功的上锁，那么导致另外
    #一方会堵塞（一直等待）到这个锁被解开为止
    mutex.acquire()
    for i in range(1000000):
        g_num += 1
    mutex.release()#用来对mutex指向的这个锁　进行解锁，，，只要开了锁，那么接下来会让所有因为
                    #这个锁　被上了锁　而堵塞的线程　进行抢着上锁

    print("---test1---g_num=%d"%g_num)

def test2():
    global g_num
    mutex.acquire()
    for i in range(1000000):
        g_num += 1
    mutex.release()

    print("---test2---g_num=%d"%g_num)

#创建一把互斥锁，这个锁默认是没有上锁的
mutex = Lock()

p1 = Thread(target=test1)
p1.start()

#time.sleep(3) #取消屏蔽之后 再次运行程序，结果会不一样，，，为啥呢？

p2 = Thread(target=test2)
p2.start()

print("---g_num=%d---"%g_num)

from threading import Thread
import threading
import time

def test1():
    #注意：
    #   1. 全局变量在多个线程中　共享，为了保证正确运行需要锁
    #   2. 非全局变量在每个线程中　各有一份，不会共享，当然了不需要加锁
    name = threading.current_thread().name
    print("----thread name is %s ----"%name)
    g_num = 100
    if name == "Thread-1": 
        g_num += 1
    else:
        time.sleep(2)
    print("--thread is %s----g_num=%d"%(name,g_num))

#def test2():
#    time.sleep(1)
#    g_num = 100
#    print("---test2---g_num=%d"%g_num)


p1 = Thread(target=test1)
p1.start()

p2 = Thread(target=test1)
p2.start()