1.利用“固定网址”+“下页”方法

同样使用豆瓣电影的网页来进行分析，https://movie.douban.com 豆瓣电影网站

#获取下一页地址
#获取下一页地址
    try:
        next_url = list.xpath('//span[@class="next"]/a/@href')[0]    #@href是获取href的地址
        if next_url:
            url = "https://movie.douban.com/top250"+ next_url
    except:
        flag = False

完整代码为：

import requests
from lxml import etree
import re

url="https://movie.douban.com/top250"
header = {"User-Agent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36"}

allMovieList=[]
flag = True
while flag:
    html = requests.get(url, headers=header).text
    list = etree.HTML(html)
    lis = list.xpath('//ol[@class="grid_view"]/li')
    for oneSelector in lis:
        name = oneSelector.xpath("div/div[2]/div[1]/a/span[1]/text()")[0]
        score = oneSelector.xpath("div/div[2]/div[2]/div/span[2]/text()")[0]
        people = oneSelector.xpath("div/div[2]/div[2]/div/span[4]/text()")[0]
        people = re.findall("(.*?)人评价",people)[0]
        oneMovieList = [name,score,people]
        allMovieList.append(oneMovieList)
    #获取下一页地址
    try:
        next_url = list.xpath('//span[@class="next"]/a/@href')[0]
        if next_url:
            url = "https://movie.douban.com/top250"+ next_url
    except:
        flag = False
print(allMovieList)

2.利用“固定网址”+“不同数字码”方法

import requests
from lxml import etree
import re

allMovieList=[]
for page in range(3):
    url = "https://movie.douban.com/top250?start=%s" % (page*25)
    print(url)
    header = {"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36"}
    html = requests.get(url, headers=header).text
    list = etree.HTML(html)
    lis = list.xpath('//ol[@class="grid_view"]/li')
    for oneSelector in lis:
        name = oneSelector.xpath("div/div[2]/div[1]/a/span[1]/text()")[0]
        score = oneSelector.xpath("div/div[2]/div[2]/div/span[2]/text()")[0]
        people = oneSelector.xpath("div/div[2]/div[2]/div/span[4]/text()")[0]
        people = re.findall("(.*?)人评价",people)[0]
        oneMovieList = [name,score,people]
        allMovieList.append(oneMovieList)
print(allMovieList)

运行结果为：