python3 xpath和requests应用

根据一个爬取豆瓣电影排名的小应用，来简单使用etree和request库。

etree使用xpath语法。

import requestsimport sslfrom lxml import etreessl._create_default_https_context = ssl._create_unverified_contextsession = requests.Session()for id in range(0, 251, 25):    URL = 'https://movie.douban.com/top250/?start=' + str(id)    req = session.get(URL)    # 设置网页编码格式    req.encoding = 'utf8'    # 将request.content 转化为 Element    root = etree.HTML(req.content)    # 选取 ol/li/div[@class="item"] 不管它们在文档中的位置    items = root.xpath('//ol/li/div[@class="item"]')    for item in items:        # 注意可能只有中文名，没有英文名；可能没有quote简评        rank, name, alias, rating_num, quote, url = "", "", "", "", "", ""        try:            url = item.xpath('./div[@class="pic"]/a/@href')[0]            rank = item.xpath('./div[@class="pic"]/em/text()')[0]            title = item.xpath('./div[@class="info"]//a/span[@class="title"]/text()')            name = title[0].encode('gb2312', 'ignore').decode('gb2312')            alias = title[1].encode('gb2312', 'ignore').decode('gb2312') if len(title) == 2 else ""            rating_num = item.xpath('.//div[@class="bd"]//span[@class="rating_num"]/text()')[0]            quote_tag = item.xpath('.//div[@class="bd"]//span[@class="inq"]')            if len(quote_tag) is not 0:                quote = quote_tag[0].text.encode('gb2312', 'ignore').decode('gb2312').replace('\xa0', '')            # 输出 排名，评分，简介            print(rank, rating_num, quote)            # 输出 中文名，英文名            print(name.encode('gb2312', 'ignore').decode('gb2312'),                  alias.encode('gb2312', 'ignore').decode('gb2312').replace('/', ','))        except:            print('faild!')            pass

程序运行结果：