python - driver.find_element_by_css_selector 在页面末尾运行缓慢

Question

我有一个 from selenium import webdriver 温度网络抓取工具，工作于 weather.com使用Python。页面开头的网络抓取工具几乎立即找到正确的高温和低温。然而，到页面末尾时，它会变得越来越慢(需要 7 秒才能结束)。这可能是因为抓取工具必须遍​​历更多 HTML 才能找到正确的数据(？)。这是代码的主要部分:

high = driver.find_element_by_css_selector('#twc-scrollabe > table > tbody > tr:nth-child(' + str(j) + ') > td.temp > div > span:nth-child(1)').text
low = driver.find_element_by_css_selector('#twc-scrollabe > table > tbody > tr:nth-child(' + str(j) + ') > td.temp > div > span:nth-child(3)').text
    date = driver.find_element_by_css_selector('#twc-scrollabe > table > tbody > tr:nth-child(' + str(j) + ') > td:nth-child(2) > div > span').text

#auth > div > div > div > div > div > form > button

#twc-scrollabe > table > tbody > tr:nth-child(1) > td:nth-child(2) > div > span
#twc-scrollabe > table > tbody > tr:nth-child(2) > td:nth-child(2) > div > span

是否有简单(或复杂)的解决方案？如果您认为没有简单的解决方案，那也会有很大的帮助(可能是这种情况？)

Answer 1

您要查找的内容是否是由 JavaScript 生成的？如果只是 HTML，您可以避免使用 headless 浏览器并使用 requests 和 bs4:

$ python test.py
Got response: 200
Today JUN 1  80°/61°
Sun   JUN 2  70°/47°
Mon   JUN 3  63°/45°
Tue   JUN 4  74°/57°
Wed   JUN 5  75°/64°
Thu   JUN 6  77°/63°
Fri   JUN 7  77°/64°
Sat   JUN 8  81°/66°
Sun   JUN 9  81°/65°
Mon   JUN 10 80°/63°
Tue   JUN 11 80°/63°
Wed   JUN 12 81°/62°
Thu   JUN 13 80°/63°
Fri   JUN 14 81°/63°
Sat   JUN 15 81°/63°
Total: 0.66s, request: 0.60s

测试.py

import requests
import time

from bs4 import BeautifulSoup

URL = 'https://weather.com/weather/tenday/l/USPA1290:1:US'


def fetch(url):
    with requests.Session() as s:
        r = s.get(URL, timeout=5)
        return r


def main():
    start_t = time.time()
    resp = fetch(URL)
    print(f'Got response: {resp.status_code}')
    html = resp.text
    bs = BeautifulSoup(html, 'html.parser')
    tds = bs.find_all('td', class_='twc-sticky-col', attrs={'headers': 'day'})
    for td in tds:
        date_time = td.find_next('span', class_='date-time')
        day_detail = td.find_next('span', class_='day-detail')
        temp = td.find_next('td', class_='temp', attrs={'headers': 'hi-lo'})
        hi_lo = '/'.join(i.text for i in temp.find_all('span', class_=''))
        print(f'{date_time.text:5} {day_detail.text:6} {hi_lo}')
    end_t = time.time()
    elapsed_t = end_t - start_t
    r_time = resp.elapsed.total_seconds()
    print(f'Total: {elapsed_t:.2f}s, request: {r_time:.2f}s')


if __name__ == '__main__':
    main()