1.什么是线程

    进程:资源单位

    线程:执行单位

    注意:每一个进程中都会自带一个线程

2.为什么要有线程

    开一个进程:

        申请内存空间   耗时

        将代码拷贝到申请的内存空间中   耗时

    开线程:

        不需要申请内存空间

    开线程的开销远远小于开进程的开销！！！

3.如何使用线程

4 子线程的两种建立方式

# 方式1'''from threading import Threadimport timedef task(name):    print('%s is running' % name)    time.sleep(1)    print('%s is over')t = Thread(target=task, args=('king',))t.start()print('主')'''# 方式 2from threading import Threadimport timeclass MyThread(Thread):    def __init__(self,name):        super().__init__()        self.name = name    def run(self):        print('%s is run'%self.name)        time.sleep(3)        print('%s is over'%self.name)t = MyThread('king')t.start()print('主')

5、线程之间的数据共享

from threading import Threadx = 100def task():    global x    x =666    print(x)t = Thread(target=task)t.start()print(x)

6、线程互斥锁

from threading import Thread,Lockimport timemutex = Lock()n = 100def task():    global n    mutex.acquire()    tmp = n    time.sleep(0.1)    n = tmp -1    mutex.release()t_list = []for i in range(100):    t = Thread(target=task)    t.start()    t_list.append(t)for t in t_list:    t.join()print(n)

7、线程的其他属性方法

from threading import Thread,active_count,current_threadimport osimport timedef task(name):    # print('%s is running'%name,os.getpid())    print('%s is running'%name,current_thread().name,current_thread().getName())    time.sleep(1)    print('%s is over'%name)def info(name):    print('%s is running' % name, current_thread().name, current_thread().getName())    time.sleep(1)    print('%s is over' % name)t = Thread(target=task,args=('关磊',))t1 = Thread(target=info,args=('关超',))t.start()t1.start()t.join()print(active_count())  # 当前存活的线程数print(os.getpid())print(current_thread().name)print(current_thread().getName())