import threading import time import requests def say_hi(name):     time.sleep(2)     print(name) def down_html(url1, name):     res = requests.get(url1).content     with open(name + '.html', 'wb') as f:         f.write(res) urls = [     ['nnzhp', 'http://www.nnzhp.cn'],     ['dsx', 'http://www.imdsx.cn'],     ['besttest', 'http://www.besttest.cn'] ] start_time = time.time() # for url in urls: #     down_html(url[1], url[0]) threads = []  # 存放刚才启动的线程 for url in urls:     t = threading.Thread(target=down_html, args=(url[1], url[0]))     t.start()     threads.append(t) for t in threads:     t.join()  # 主线程等待子线程结束 end_time = time.time() print(end_time - start_time) # for i in range(10): #     t = threading.Thread(target=say_hi, args=('小黑',))  # 启动线程 #     t.start()

100个url,启动5个线程

import threading import time urls = list(range(100)) def p(url):     for u in url:         print(u) start = 0 end = 20 for i in range(5):     url_new = urls[start:end]     start += 20     end += 20     t = threading.Thread(target=p, args=(url_new,))     t.start()