Python多进程、多线程、协程典型示例解析(最新推荐)

import multiprocessing
import time
# 计算平方的任务函数
def calculate_square(number):
    total = 0
    for n in range(number):
        total += n ** 2
    print(f"计算结果：{total}")
if __name__ == "__main__":  # 必须加这句，否则Windows系统会报错
    # 创建4个进程
    processes = []
    numbers = [10_000_000, 10_000_000, 10_000_000, 10_000_000]  # 四个大数
    # 记录开始时间
    start_time = time.time()
    # 创建并启动进程
    for num in numbers:
        p = multiprocessing.Process(target=calculate_square, args=(num,))
        processes.append(p)
        p.start()  # 启动进程（会立即返回，不会等待完成）
    # 等待所有进程完成
    for p in processes:
        p.join()  # 阻塞主进程，直到子进程结束
    # 计算总耗时
    print(f"总耗时：{time.time() - start_time:.2f}秒")

import threading
import time
import requests
# 全局变量（线程共享）
download_complete = False
def download_file(url):
    global download_complete
    print("开始下载文件...")
    response = requests.get(url)
    with open("bigfile.iso", "wb") as f:
        f.write(response.content)
    download_complete = True
    print("\n下载完成！")
def show_progress():
    while not download_complete:
        print(".", end="", flush=True)  # 不换行输出点
        time.sleep(0.5)
if __name__ == "__main__":
    # 创建两个线程
    download_thread = threading.Thread(
        target=download_file, 
        args=("https://example.com/large-file.iso",)
    )
    progress_thread = threading.Thread(target=show_progress)
    # 启动线程
    download_thread.start()
    progress_thread.start()
    # 等待下载线程完成
    download_thread.join()
    progress_thread.join()  # 需要手动停止进度条线程

import asyncio
import aiohttp  # 需要安装：pip install aiohttp
async def fetch_page(url):
    async with aiohttp.ClientSession() as session:  # 创建会话
        async with session.get(url) as response:    # 发起请求
            return await response.text()           # 异步等待响应
async def main():
    urls = [
        "https://www.baidu.com",
        "https://www.taobao.com",
        "https://www.jd.com"
    ]
    # 创建任务列表
    tasks = [fetch_page(url) for url in urls]
    # 并行执行所有任务
    pages = await asyncio.gather(*tasks)  # 关键点：聚集任务
    # 输出结果
    for url, content in zip(urls, pages):
        print(f"{url} → 长度：{len(content)}")
# 启动事件循环
asyncio.run(main())  # Python 3.7+