Python中的并发编程-2

from multiprocessing import Process, current_process
from time import sleep


def sub_task(content, nums):
    # 通过current_process函数获取当前进程对象
    # 通过进程对象的pid和name属性获取进程的ID号和名字
    print(f'PID: {current_process().pid}')
    print(f'Name: {current_process().name}')
    # 通过下面的输出不难发现，每个进程都有自己的nums列表，进程之间本就不共享内存
    # 在创建子进程时复制了父进程的数据结构，三个进程从列表中pop(0)得到的值都是20
    counter, total = 0, nums.pop(0)
    print(f'Loop count: {total}')
    sleep(0.5)
    while counter < total:
        counter += 1
        print(f'{counter}: {content}')
        sleep(0.01)


def main():
    nums = [20, 30, 40]
    # 创建并启动进程来执行指定的函数
    Process(target=sub_task, args=('Ping', nums)).start()
    Process(target=sub_task, args=('Pong', nums)).start()
    # 在主进程中执行sub_task函数
    sub_task('Good', nums)


if __name__ == '__main__':
    main()

import os

print(f'PID: {os.getpid()}')
pid = os.fork()
if pid == 0:
    print(f'子进程 - PID: {os.getpid()}')
    print('Todo: 在子进程中执行的代码')
else:
    print(f'父进程 - PID: {os.getpid()}')
    print('Todo: 在父进程中执行的代码')

import concurrent.futures

PRIMES = [
    1116281,
    1297337,
    104395303,
    472882027,
    533000389,
    817504243,
    982451653,
    112272535095293,
    112582705942171,
    112272535095293,
    115280095190773,
    115797848077099,
    1099726899285419
] * 5


def is_prime(n):
    """判断素数"""
    for i in range(2, int(n ** 0.5) + 1):
        if n % i == 0:
            return False
    return n != 1


def main():
    """主函数"""
    with concurrent.futures.ThreadPoolExecutor(max_workers=16) as executor:
        for number, prime in zip(PRIMES, executor.map(is_prime, PRIMES)):
            print('%d is prime: %s' % (number, prime))


if __name__ == '__main__':
    main()

import concurrent.futures

PRIMES = [
    1116281,
    1297337,
    104395303,
    472882027,
    533000389,
    817504243,
    982451653,
    112272535095293,
    112582705942171,
    112272535095293,
    115280095190773,
    115797848077099,
    1099726899285419
] * 5


def is_prime(n):
    """判断素数"""
    for i in range(2, int(n ** 0.5) + 1):
        if n % i == 0:
            return False
    return n != 1


def main():
    """主函数"""
    with concurrent.futures.ProcessPoolExecutor(max_workers=16) as executor:
        for number, prime in zip(PRIMES, executor.map(is_prime, PRIMES)):
            print('%d is prime: %s' % (number, prime))


if __name__ == '__main__':
    main()

import os

print(os.cpu_count())

from multiprocessing import Process
from time import sleep

counter = 0


def sub_task(string):
    global counter
    while counter < 50:
        print(string, end='', flush=True)
        counter += 1
        sleep(0.01)

        
def main():
    Process(target=sub_task, args=('Ping', )).start()
    Process(target=sub_task, args=('Pong', )).start()


if __name__ == '__main__':
    main()

import time
from multiprocessing import Process, Queue


def sub_task(content, queue):
    counter = queue.get()
    while counter < 50:
        print(content, end='', flush=True)
        counter += 1
        queue.put(counter)
        time.sleep(0.01)
        counter = queue.get()


def main():
    queue = Queue()
    queue.put(0)
    p1 = Process(target=sub_task, args=('Ping', queue))
    p1.start()
    p2 = Process(target=sub_task, args=('Pong', queue))
    p2.start()
    while p1.is_alive() and p2.is_alive():
        pass
    queue.put(50)


if __name__ == '__main__':
    main()