就业DAY5_多任务_进程，进程池，队列教程

import time
import multiprocessing

def sing():
    """"唱歌 5秒钟"""
    for i in range(5):
        print("----正在唱歌----")
        time.sleep(1)


def dance():
    """跳舞 子线程"""
    for i in range(5):
        print("----正在跳舞----")
        time.sleep(1)

def main():
    p1 = multiprocessing.Process(target=sing)
    p2 = multiprocessing.Process(target=dance)
    p1.start()  
    p2.start()


if __name__ == "__main__":
    main()

Queue队列 先进先出

多进程之间通过Queue来实现数据共享

import multiprocessing


def download_from_web(q):
    # 模拟从网上下载的数据
    data = [11, 22, 33, 44]
    # 向队列中写入数据
    for temp in data:
        q.put(temp)
    print("---下载器已经下载完了数据并且存入队列中")


def analysis_data(q):
    """数据说明"""
    waitting_analysis_data  = list()
    # waitting = []
    # 从队列中获取数据
    while True:
        data = q.get()
        waitting_analysis_data.append(data)
        if q.empty():
            break
    print(waitting_analysis_data)


def main():
    # 1 创建一个队列
    q = multiprocessing.Queue()

    # 2 创建多个进程，将队列的引用作为实参进行传递到里面
    p1 = multiprocessing.Process(target=download_from_web, args=(q,))
    p2 = multiprocessing.Process(target=analysis_data, args=(q,))
    p1.start()
    p2.start()


if __name__ == "__main__":
    main()

from multiprocessing import Pool
import time
import os
import random

def  worker(msg):
    t_start = time.time()
    print("%s开始执行，进程编号为%d" % (msg, os.getpid()))
    # random.random() 随机生成0-1之间的浮点数
    time.sleep(random.random()*2)
    t_stop = time.time()
    print(msg,"执行完毕,耗时%0.2f" % (t_stop- t_start))

# 定义一个进程池 最大进程数3
po = Pool(3)
for i in range(0, 9):
    # Pool().apply async (要调用的目标，（传递给目标的参数元组）)
    # 每次循环将会用空闲出来的子进程去调用目标
    po.apply_async(worker, args=(i,))
print("----start----")
po.close()  # 关闭进程池 关闭后po不再接受新的请求
po.join()  # 等待po中所有子进程执行完成，必须放在close语句之后
print("----end----")

----start----
0开始执行，进程编号为19288
1开始执行，进程编号为19289
2开始执行，进程编号为19290
1 执行完毕,耗时0.55
3开始执行，进程编号为19289
2 执行完毕,耗时1.35
4开始执行，进程编号为19290
3 执行完毕,耗时0.88
5开始执行，进程编号为19289
0 执行完毕,耗时1.51
6开始执行，进程编号为19288
4 执行完毕,耗时0.55
7开始执行，进程编号为19290
5 执行完毕,耗时1.27
8开始执行，进程编号为19289
7 执行完毕,耗时0.84
8 执行完毕,耗时0.23
6 执行完毕,耗时1.53
----end----

import multiprocessing
import os

def copy_file(q, file_name, old_folder_name, new_folder_name):
    """完成文件的复制"""
    # print("%s,%s,%s" % (old_folder_name, file_name, new_folder_name))
    old_f = open(old_folder_name + "/" + file_name, "rb")
    content = old_f.read()
    old_f.close()

    new_f = open(new_folder_name + "/" + file_name, "wb" )
    new_f.write(content)
    new_f.close()
    # 如果拷贝完了文件，那么就向队列中写入一个消息，表示已经完成
    q.put(file_name)


def main():
    # 1 输入文件夹名，获取用户要copy的文件夹的名字
    old_folder_name = input("请输入要拷贝的文件夹的名字")

    # 2 创建一个新的文件夹
    try:
        new_folder_name = old_folder_name + "[复件]"
        os.mkdir(new_folder_name)
    except:
        pass

    # 3 获取文件夹中所有待copy文件名 listdir()
    file_names = os.listdir(old_folder_name)
    print(file_names)

    # 4 创建进程池
    po = multiprocessing.Pool(5)

    # 5 创建队列
    q = multiprocessing.Manager().Queue()

    # 6 向进程池中添加拷贝文件的任务
    for file_name in file_names:
        po.apply_async(copy_file, args=(q, file_name, old_folder_name, new_folder_name))

    po.close()
    # po.join()
    all_file_name = len(file_names)  # 测一下所有文件个数
    copy_ok_num = 0
    while True:
        file_name = q.get()
        # print("已经完成拷贝%s" % file_name)
        copy_ok_num += 1
        print("\r拷贝的进度为：%.2f%%" % (copy_ok_num*100/all_file_name),end="")
        if copy_ok_num >= all_file_name:
            break


if __name__ == "__main__":
    main()

栈 先进后出