python并行设计的实现

import threading
import time

def worker(num):
    """线程工作函数"""
    print(f"线程 {num} 开始")
    time.sleep(2)
    print(f"线程 {num} 结束")

threads = []

for i in range(5):
    t = threading.Thread(target=worker, args=(i,))
    threads.append(t)
    t.start()

for t in threads:
    t.join()

print("所有线程已完成")

from multiprocessing import Process
import time

def worker(num):
    """进程工作函数"""
    print(f"进程 {num} 开始")
    time.sleep(2)
    print(f"进程 {num} 结束")

processes = []

for i in range(5):
    p = Process(target=worker, args=(i,))
    processes.append(p)
    p.start()

for p in processes:
    p.join()

print("所有进程已完成")

from concurrent.futures import ThreadPoolExecutor
import time

def worker(num):
    print(f"线程 {num} 开始")
    time.sleep(2)
    print(f"线程 {num} 结束")

with ThreadPoolExecutor(max_workers=5) as executor:
    futures = [executor.submit(worker, i) for i in range(5)]
    for future in futures:
        future.result()

print("所有线程已完成")

from concurrent.futures import ProcessPoolExecutor
import time

def worker(num):
    print(f"进程 {num} 开始")
    time.sleep(2)
    print(f"进程 {num} 结束")

with ProcessPoolExecutor(max_workers=5) as executor:
    futures = [executor.submit(worker, i) for i in range(5)]
    for future in futures:
        future.result()

print("所有进程已完成")

from concurrent.futures import ProcessPoolExecutor
from PIL import Image
import os

def process_image(image_path):
    img = Image.open(image_path)
    img = img.convert("L")  # 转换为灰度图
    img.save(f"processed/{os.path.basename(image_path)}")
    print(f"{image_path} 已处理")

image_paths = ["image1.jpg", "image2.jpg", "image3.jpg"]

if not os.path.exists("processed"):
    os.makedirs("processed")

with ProcessPoolExecutor(max_workers=4) as executor:
    executor.map(process_image, image_paths)

print("所有图像已处理")