Python爬虫爬取豆瓣数据XPath的使用

实现步骤：

1. 确定网页源码

2. 把网页源码生成一个element对象

3. 通过element对象实现XPath语法

4. 保存数据

目标页面如图：

首先进行url分析：

第一页、第二页、第三页的url如下：

https://movie.douban.com/top250

https://movie.douban.com/top250?start=25&filter=

https://movie.douban.com/top250?start=50&filter=

其中，第一页也等价于

https://movie.douban.com/top250?start=0&filter=

页面分析：

这里一个

• 标签就代表一部电影。

且所有想要获取的目标数据都在

标签中。

1.导包

from lxml import etree

import requests

import csv

2.拿到目标url

doubanUrl = ‘https://movie.douban.com/top250?start={}&filter=’

3.获取网页源码

def getSource(url):

headers = {

‘User-Agent’: ‘Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36’}

response = requests.get(url, headers=headers)

response.encoding = ‘utf-8’

return response.text

4.解析数据

def getEveryItem(source):

html_element = etree.HTML(source)

class = ‘info’ 电影的名字，评分，引言，详情页的

movieItemList = html_element.xpath(“//div[@class=‘info’]”)

定义一个空列表，添加字典数据

movieList = []

for eachMovie in movieItemList:

定义一个字典保存每部电影的数据

movieDict = {}

标题

title = eachMovie.xpath(“div[@class=‘hd’]/a/span[@class=‘title’]/text()”)

副标题

otherTitle = eachMovie.xpath(“div[@class=‘hd’]/a/span[@class=‘other’]/text()”)

详情页url

star = eachMovie.xpath(“div[@class=‘bd’]/div[@class=‘star’]/span[@class=‘rating_num’]/text()”)[0]

link = eachMovie.xpath(‘div[@class=“hd”]/a/@href’)[0]

quote = eachMovie.xpath(“div[@class=‘bd’]/p[@class=‘quote’]/span/text()”)

非空判断

if quote:

quote = quote[0]

else:

quote = ‘’

保存数据，标题是主标题+副标题

movieDict[‘title’] = ‘’.join(title+otherTitle)

movieDict[‘url’] = link

movieDict[‘star’] = star

movieDict[‘quote’] = quote

#print(movieDict)

movieList.append(movieDict)

return movieList

5.保存数据

def writeData(movieList):

with open(‘douban.csv’, ‘w’, encoding=‘utf-8’ , newline=‘’) as f:

writer = csv.DictWriter(f, fieldnames=[‘title’, ‘star’, ‘quote’, ‘url’])