python多线程超级详细！

# 守护线程
import threading
import time


class MyThreading(threading.Thread):
    def __init__(self, name):
        super(MyThreading, self).__init__()
        self.name = name

    # 线程要运行的代码
    def run(self):
        print("我是线程%s" % self.name)
        time.sleep(2)
        print("线程%s运行结束" % self.name)


t1 = MyThreading(1)
t2 = MyThreading(2)
start_time = time.time()
t1.setDaemon(True)
t1.start()
t2.setDaemon(True)
t2.start()
end_time = time.time()
print("两个线程一共的运行时间为：", end_time-start_time)
print("主线程结束")
守护线程

# -*- coding:utf8  -*-
import threading
import time

num = 100
threading_list = []


def fun():
    global num
    print("get num:", num)
    num += 1
    time.sleep(1)


for x in range(200):
    t = threading.Thread(target=fun)
    t.start()
    threading_list.append(t)

for x in threading_list:
    x.join()

print("nun:", num)

import random
import threading
import time
num = 100
threading_list = []


def fun():
    global num
    time.sleep(random.random())
    lock.acquire() # 加锁
    print("get num:", num, threading.current_thread())
    num += 1
    lock.release()  # 释放锁


# 实例化锁对象
lock = threading.Lock()
for x in range(200):
    t = threading.Thread(target=fun)
    t.start()
    threading_list.append(t)

for x in threading_list:
    x.join()

print("num:", num)

机智的同学可能会问到这个问题，就是既然你之前说过了，Python已经有一个GIL来保证同一时间只能有一个线程来执行了，为什么这里还需要lock? 注意啦，这里的lock是用户级的lock,跟那个GIL没关系 ，具体我们通过下图来看一下+配合我现场讲给大家，就明白了。

那你又问了， 既然用户程序已经自己有锁了，那为什么C python还需要GIL呢？加入GIL主要的原因是为了降低程序的开发的复杂度，比如现在的你写python不需要关心内存回收的问题，因为Python解释器帮你自动定期进行内存回收，你可以理解为python解释器里有一个独立的线程，每过一段时间它起wake up做一次全局轮询看看哪些内存数据是可以被清空的，此时你自己的程序 里的线程和 py解释器自己的线程是并发运行的，假设你的线程删除了一个变量，py解释器的垃圾回收线程在清空这个变量的过程中的clearing时刻，可能一个其它线程正好又重新给这个还没来及得清空的内存空间赋值了，结果就有可能新赋值的数据被删除了，为了解决类似的问题，python解释器简单粗暴的加了锁，即当一个线程运行时，其它人都不能动，这样就解决了上述的问题，  这可以说是Python早期版本的遗留问题。

import threading, time


def run1():
    lock.acquire()
    print("grab the first part data")
    global num
    num += 1
    lock.release()
    return num


def run2():
    lock.acquire()
    print("grab the second part data")
    global num2
    num2 += 1
    lock.release()
    return num2


def run3():
    lock.acquire()
    res = run1()
    print('--------between run1 and run2-----')
    res2 = run2()
    lock.release()
    print(res, res2)


if __name__ == '__main__':
    num, num2 = 0, 0
    lock = threading.RLock()
    for i in range(3):
        t = threading.Thread(target=run3)
        t.start()

while threading.active_count() != 1:
    print(threading.active_count())
else:
    print('----all threads done---')
    print(num, num2)

import threading

data_list = []

lock_object = threading.RLock()


def task():
    print("开始")
    for i in range(1000000):
        data_list.append(i)
    print(len(data_list))


for i in range(2):
    t = threading.Thread(target=task)
    t.start()

# -*- coding:GBK -*-
import threading
import time

sum_1 = 0
def run(i):
    global sum_1
    time.sleep(1)
    # lock.acquire()
    semaphore.acquire()
    sum_1 += 1
    print("线程%s来了,并修改了sum_1的值为：%s" % (i, sum_1))
    semaphore.release()
    # lock.release()

# lock = threading.Lock()
semaphore = threading.BoundedSemaphore(5)

for x in range(10):
    t = threading.Thread(target=run, args=(x,))
    t.start()

while threading.active_count() != 1:
    pass

print("程序结束")

import threading
import time

def light():
    count = 1
    event.set()  # 设置标志位 True
    while True:
        if count <= 10:
            print("现在是绿灯")
            time.sleep(1)
        elif count <= 15:
            print("现在是红灯")
            event.clear()   # 清空标志位(将标志位改为false)
            time.sleep(1)
        else:
            count = 0
            event.set()
        count += 1


def car(name):
    while True:
        if event.is_set():
            print("----------%s在起飞-------------" % name)
            time.sleep(1)
        else:
            print("---------%s在等红灯---------------" % name)
            event.wait()   # 等待标志位被设置位True程序才继续往下运行


event = threading.Event()
light_1 = threading.Thread(target=light)
light_1.start()
for x in range(5):
    car_1 = threading.Thread(target=car, args=("马自达"+str(x),))
    car_1.start()

import queue
import threading
import time

exitFlag = 0

class myThread (threading.Thread):
    def __init__(self, threadID, name, q):
        threading.Thread.__init__(self)
        self.threadID = threadID
        self.name = name
        self.q = q
    def run(self):
        print ("开启线程：" + self.name)
        process_data(self.name, self.q)
        print ("退出线程：" + self.name)

def process_data(threadName, q):
    while not exitFlag:
        queueLock.acquire()
        if not workQueue.empty():
            data = q.get()
            queueLock.release()
            print ("%s processing %s" % (threadName, data))
        else:
            queueLock.release()
        time.sleep(1)

threadList = ["Thread-1", "Thread-2", "Thread-3"]
nameList = ["One", "Two", "Three", "Four", "Five"]
queueLock = threading.Lock()
workQueue = queue.Queue(10)
threads = []
threadID = 1

# 创建新线程
for tName in threadList:
    thread = myThread(threadID, tName, workQueue)
    thread.start()
    threads.append(thread)
    threadID += 1

# 填充队列
queueLock.acquire()
for word in nameList:
    workQueue.put(word)
queueLock.release()

# 等待队列清空
while not workQueue.empty():
    pass

# 通知线程是时候退出
exitFlag = 1

# 等待所有线程完成
for t in threads:
    t.join()
print ("退出主线程")

以上程序执行结果：

开启线程：Thread-1
开启线程：Thread-2
开启线程：Thread-3
Thread-3 processing One
Thread-1 processing Two
Thread-2 processing Three
Thread-3 processing Four
Thread-1 processing Five
退出线程：Thread-3
退出线程：Thread-2
退出线程：Thread-1
退出主线程

# 生产者/消费者
import threading
import queue
import time


# 生产者
def producer(name):
    count = 1
    while True:
        p.put("{}骨头{}".format(name, count))
        print("骨头{}被{}生产".format(count, name).center(60, "*"))
        count += 1
        time.sleep(0.1)


# 消费者
def consumer(name):
    while True:
        print("{}被{}吃掉了".format(p.get(), name))


# 实例化队列对象
p = queue.Queue(10)
# 创建生产者线程
producer_threading1 = threading.Thread(target=producer, args=("飞某人",))
producer_threading2 = threading.Thread(target=producer, args=("Alex",))
# 创建消费者线程
consumer_threading1 = threading.Thread(target=consumer, args=("张三",))
consumer_threading2 = threading.Thread(target=consumer, args=("李四",))
producer_threading1.start()
producer_threading2.start()
consumer_threading1.start()
consumer_threading2.start()