Python-进程与线程

多进程

多进程2

import time
from multiprocessing import Process
import os


def dance(num, name):
    print('Process of basketball is %s.' % os.getpid())
    for i in range(num):
        print(name+' is playing basketball right now.')
        time.sleep(0.5)


def sing(num, name):
    print('Process of the guitar is %s.' % os.getpid())
    for i in range(num):
        print(name+' is playing the guitar next door.')
        time.sleep(0.5)


if __name__ == '__main__':
    print('Parent process: %s.' % os.getpid())
    # 下面这两个是在创建子进程对象并指定执行的任务名
    # target就是指定函数名,args就是参数
    # 若使用元组,参数位置必须按照定义的函数的顺序来写
    p = Process(target=dance, args=(2, 'Bob'))  # 只传一个参数时，加个逗号，否则解释器会认为这不是一个元祖而是一个数字
    f = Process(target=sing, kwargs={'num': 2, 'name': 'Eric'})  # 使用字典时,甚至可以不按顺序,只要参数名称对就可以
    # 启动子进程并执行任务
    p.start()
    f.start()
    p.join()
    f.join()
    print('Boys love these things.')

 再来看看进程间的通信：

import os
import time
import random
from multiprocessing import Process, Queue


def write(p):
    print('Process to write: %s.' % os.getpid())
    for value in ['A', 'B', 'C']:
        print('Put process %s into queue.' % value)
        p.put(value)
        time.sleep(random.random())


def read(q):
    print('Process to read: %s' % os.getpid())
    while True:
        value = q.get(True)
        print('Get value %s from queue.' % value)


if __name__ == '__main__':
    queue = Queue()
    pw = Process(target=write, args=(queue, ))
    pr = Process(target=read, args=(queue, ))
    pw.start()
    pr.start()
    pw.join()
    pr.terminate()