进程是由CPU给分配的执行单元，比较消耗空间和内存

创建、使用线程

import threading# 进程
# 线程
from time import sleepdef download():list1 = ["girl.png", "boy.png", "child.png"]for l in list1:print(l)sleep(1.5)print("下载{}成功！".format(l), end='\n')def listen():list1 = ["爱情买卖", "大风吹", "小米"]for l in list1:print("正在听{}成功！".format(l), end='\n')sleep(1.5)if __name__ == '__main__':t1 = threading.Thread(target=download)t2 = threading.Thread(target=listen)t1.start()t2.start()n = 1while True:if n == 100:breaksleep(1.5)print(n)n += 1

线程的状态

线程共享全局变量

import threading
from multiprocessing import Process
from time import sleepmoney = 1000def run1():global moneyfor i in range(100):money -= 1def run2():global moneyfor i in range(100):money -= 1if __name__ == '__main__':p1 = threading.Thread(target=run1)p2 = threading.Thread(target=run2)p1.start()p2.start()p1.join()p2.join()print(money)

线程同步（加锁/lock/rlock/GIL）

python解释器会在创建线程的时候默认加锁（GIL全局解释器锁）

import threading
import random
import timelock = threading.Lock()
list1 = [0] * 10def task1():lock.acquire()for i in range(len(list1)):list1[i] = itime.sleep(0.5)lock.release()def task2():lock.acquire()for i in range(len(list1)):print(list1[i])time.sleep(0.5)lock.release()if __name__ == '__main__':t1 = threading.Thread(target=task1)t2 = threading.Thread(target=task2)t2.start()t1.start()print("over~~~~~")t1.join()t2.join()print(list1)

死锁

import threading
import random
import timelock1 = threading.Lock()
lock2 = threading.Lock()def task1():print("任务一")if lock1.acquire():print("Lock1--->任务1")time.sleep(2.5)if lock2.acquire(timeout=2):print("Lock2--->任务1")time.sleep(2.5)lock1.release()def task2():print("任务二")if lock2.acquire():print("Lock2--->任务2")time.sleep(2.5)if lock1.acquire(timeout=2):print("Lock1--->任务2")time.sleep(2.5)lock2.release()if __name__ == '__main__':t1 = threading.Thread(target=task1)t2 = threading.Thread(target=task2)t2.start()t1.start()

线程间的通信（注意与进程使用的API不一样）

from multiprocessing import Queue
from multiprocessing import Process
from time import sleep
import threading
import queuedef product(queue):n = 1while True:if n == 10:breakprint("生产者，生产{}".format(n))queue.put(n)sleep(1)n += 1queue.put(None)print("生成完毕！")def consume(queue):n = 1while True:if n == 10:breakm = queue.get()print("消费者，消费{}".format(m))sleep(3)n += 1print("消费完毕！")if __name__ == '__main__':# queue = Queue(5)# p1 = Process(target=down_load, args=(queue,))# p2 = Process(target=getfile, args=(queue,))que = queue.Queue(5)th1 = threading.Thread(target=product, args=(que,))th2 = threading.Thread(target=consume, args=(que,))th1.start()th2.start()