from multiprocessing import Manager,Process,Lockdef work(d,lock):with lock:d['count'] -= 1if __name__ == '__main__':lock = Lock()with Manager() as m:   # m = Manager()dic = m.dict({'count':100})p_lst = []for i in range(10):p = Process(target=work, args=(dic, lock))p_lst.append(p)p.start()for p in p_lst:p.join()print(dic)
#{'count': 90}

with ......一大段语句
dis模块
python的上下文管理
在执行一大段语句之前，自动做某个操作  open
在执行一大段语句之后，自动做某个操作  close面向对象的魔术方法（双下杠杠方法）

# 回调函数 in Poolimport os
from multiprocessing import Pooldef func(i):print('第一个任务', os.getpid())return '*'*idef call_back(res):   #回调函数print('回调函数：', os.getpid())print('res--->', res)if __name__ == '__main__':p = Pool()print('主进程', os.getpid())p.apply_async(func, args=(1,), callback=call_back)p.close()p.join()

import re
from urllib.request import urlopen
from multiprocessing import Poolurl_lst = ['http://www.baidu.com','http://www.sohu.com','http://www.sogou.com','http://www.4399.com','http://www.cnblogs.com',
]def get_url(url):response = urlopen(url)ret = re.search('www\.(.*?)\.com', url)print('%s finished' % ret.group(1))return ret.group(1),response.read()def call(content):url,con = contentwith open(url+'.html', 'wb')as f:f.write(con)
if __name__ == '__main__':p = Pool()for url in url_lst:p.apply_async(get_url,args=(url,),callback=call)p.close()p.join()

子进程去访问网页，主进程处理网页的结果

# 并发import os
from threading import Threaddef func(i):print('子线程：', i, os.getpid())print('主线程', os.getpid())
for i in range(10):t = Thread(target=func, args=(i,))t.start()

# 进程和线程的差距import os
import time
from threading import Thread
from multiprocessing import Processdef func(i):print('子：', os.getpid())if __name__ == '__main__':start = time.time()t_lst = []for i in range(100):t = Thread(target=func, args=(i,))t.start()t_lst.append(t)for t in t_lst:t.join()end = time.time()-startstart = time.time()t_lst = []for i in range(100):p = Process(target=func, args=(i,))p.start()t_lst.append(p)for p in t_lst:p.join()end2 = time.time()-startprint(end, end2)
#0.0279843807220459 13.582834720611572

# 线程间的数据共享from threading import Threadnum = 100
def func():global numnum -= 1            #每个线程都-1

t_lst = []
for i in range(100):t = Thread(target=func)   #创建一百个线程
    t.start()t_lst.append(t)
for t in t_lst:t.join()
print(num)   #0 

Thread实例对象的方法# isAlive(): 返回线程是否活动的。# getName(): 返回线程名。# setName(): 设置线程名。

threading模块提供的一些方法：# threading.currentThread(): 返回当前的线程变量。# threading.enumerate(): 返回一个包含正在运行的线程的list。正在运行指线程启动后、结束前，不包括启动前和终止后的线程。# threading.activeCount(): 返回正在运行的线程数量，与len(threading.enumerate())有相同的结果。

from threading import currentThread,Thread
def func():time.sleep(2)t = Thread(target=func)
t.start()
print(t.is_alive())    #True（判断线程是否活着）
print(t.getName())  #Tread-1
t.setName('tt')
print(t.getName())   #tt（改名字）def func():print('子线程：', currentThread().ident)time.sleep(2)
print('主线程：',currentThread().ident)
t = Thread(target=func)
t.start()
#currentThread().ident返回线程的pidfrom threading import enumerate
def func():print('子进程：', currentThread().ident)time.sleep(2)print('主进程：', currentThread().ident)
for i in range(10):t = Thread(target=func)t.start()
print(len(enumerate()))
#enumerate()返回一个包含正在运行的线程的list，len(list)from threading import activeCount
def func():print('子线程：', currentThread().ident)time.sleep(2)print('主线程：', currentThread().ident)
for i in range(10):t = Thread(target=func)t.start()
print(activeCount())
#activeCount()返回正在运行的线程数量，与len(threading.enumerate())有相同的结果

示例

import time
from threading import Threaddef func():while True:time.sleep(1)print(123)def func2():print('func2 start')time.sleep(3)print('func2 end')t1 = Thread(target=func)
t2 = Thread(target=func2)
t1.setDaemon(True)
t1.start()
t2.start()
print('主线程代码结束')
# func2 start
#主线程代码结束
#123
#123
#func2 end