03步批量抓取豆瓣影评前250电影名单python结果循环输出

from urllib.request import urlopen, Request
from lxml import etree
#构造函数，抓取第i页信息

    #  构造第i页的网址


def crow(i):
    url = 'https://movie.douban.com/top250?start=%s&filter='
    headers = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36'}
    ret = Request(url, headers=headers)
    res = urlopen(ret)
    html = res.read().decode('utf-8')
    print(i)
    print("开始")
    html = etree.HTML(html)
    datas = html.xpath('//ol[@class="grid_view"]/li')
    a=0
    for data in datas:
        data_title=data.xpath('div/div[2]/div[@class="hd"]/a/span[1]/text()')
        data_info=data.xpath('div/div[2]/div[@class="bd"]/p[1]/text()')
        data_quote=data.xpath('div/div[2]/div[@class="bd"]/p[2]/span/text()')
        data_score=data.xpath('div/div[2]/div[@class="bd"]/div/span[@class="rating_num"]/text()')
        data_num=data.xpath('div/div[2]/div[@class="bd"]/div/span[4]/text()')
        data_picurl=data.xpath('div/div[1]/a/img/@src')
        print("No: "+str(i*25+a+1))
        print(data_title)
        #保存电影信息到txt文件，下载封面图片
        with open('douban250.txt','a',encoding='utf-8')as f:
            #封面图片保存路径和文件名
            picname='F:/top250/'+str(i*25+a+1)+'.jpg'
            f.write("No: "+str(i*25+a+1)+'\n')
            f.write(data_title[0]+'\n')
            f.write(str(data_info[0]).strip()+'\n')
            f.write(str(data_info[1]).strip()+'\n')
            #因为发现有几部电影没有quote，所以这里加个判断，以免报错
            if data_quote:
                f.write(data_quote[0]+'\n')
            f.write(data_score[0]+'\n')
            f.write(data_num[0]+'\n')
            f.write('\n'*3)
            #下载封面图片到本地，路径为picname

        a+=1
for i in range(100):
    crow(i)