Python的xpath数据解析案例分析

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xpath基本概念

xpath解析：最常用且最便捷高效的一种解析方式。通用性强。

xpath解析原理

1.实例化一个etree的对象，且需要将被解析的页面源码数据加载到该对象中

2.调用etree对象中的xpath方法结合xpath表达式实现标签的定位和内容的捕获。

环境安装

pip install lxml

如何实例化一个etree对象

from lxml import etree

1.将本地的html文件中的远吗数据加载到etree对象中：

etree.parse(filePath)

2.可以将从互联网上获取的原码数据加载到该对象中：

etree.HTML('page_text')

xpath(‘xpath表达式’)

1./:表示的是从根节点开始定位。表示一个层级

2.//:表示多个层级。可以表示从任意位置开始定位

3.属性定位：//div[@class='song'] tag[@attrName='attrValue']

4.索引定位：//div[@class='song']/p[3] 索引从1开始的

5.取文本：

• /text()获取的是标签中直系的文本内容

• //text()标签中非直系的文本内容（所有文本内容）

6.取属性：/@attrName ==>img/src

xpath爬取58二手房实例

完整代码

from lxml import etreeimport requestsif __name__ == '__main__':    headers = {        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36'    }    url = 'https://xa.58.com/ershoufang/'    page_text = requests.get(url=url,headers=headers).text    tree = etree.HTML(page_text)    div_list = tree.xpath('//section[@class="list"]/div')    fp = open('./58同城二手房.txt','w',encoding='utf-8')    for div in div_list:        title = div.xpath('.//div[@class="property-content-title"]/h4/text()')[0]        print(title)        fp.write(title+'\n'+'\n')

xpath图片解析下载实例

完整代码

import requests,osfrom lxml import etreeif __name__ == '__main__':    headers = {        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36'    }    url = 'https://pic.netbian.com/4kmeinv/'    page_text = requests.get(url=url,headers=headers).text    tree = etree.HTML(page_text)    li_list = tree.xpath('//div[@class="slist"]/ul/li/a')    if not os.path.exists('./piclibs'):        os.mkdir('./piclibs')    for li in li_list:        detail_url ='https://pic.netbian.com' + li.xpath('./img/@src')[0]        detail_name = li.xpath('./img/@alt')[0]+'.jpg'        detail_name = detail_name.encode('iso-8859-1').decode('GBK')        detail_path = './piclibs/' + detail_name        detail_data = requests.get(url=detail_url, headers=headers).content        with open(detail_path,'wb') as fp:            fp.write(detail_data)            print(detail_name,'seccess!!')

xpath爬取全国城市名称实例

完整代码

import requestsfrom lxml import etreeif __name__ == '__main__':    url = 'https://www.aqistudy.cn/historydata/'    headers = {        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.141 Safari/537.36',    }    page_text = requests.get(url=url,headers=headers).content.decode('utf-8')    tree = etree.HTML(page_text)    #热门城市   //div[@class="bottom"]/ul/li    #全部城市   //div[@class="bottom"]/ul/div[2]/li    a_list = tree.xpath('//div[@class="bottom"]/ul/li | //div[@class="bottom"]/ul/div[2]/li')    fp = open('./citys.txt','w',encoding='utf-8')    i = 0    for a in a_list:        city_name = a.xpath('.//a/text()')[0]        fp.write(city_name+'\t')        i=i+1        if i == 6:            i = 0            fp.write('\n')    print('爬取成功')

xpath爬取简历模板实例

完整代码

import requests,osfrom lxml import etreeif __name__ == '__main__':    url = 'https://sc.chinaz.com/jianli/free.html'    headers = {        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.141 Safari/537.36',    }    page_text = requests.get(url=url,headers=headers).content.decode('utf-8')    tree = etree.HTML(page_text)    a_list = tree.xpath('//div[@class="box col3 ws_block"]/a')    if not os.path.exists('./简历模板'):        os.mkdir('./简历模板')    for a in a_list:        detail_url = 'https:'+a.xpath('./@href')[0]        detail_page_text = requests.get(url=detail_url,headers=headers).content.decode('utf-8')        detail_tree = etree.HTML(detail_page_text)        detail_a_list = detail_tree.xpath('//div[@class="clearfix mt20 downlist"]/ul/li[1]/a')        for a in detail_a_list:            download_name = detail_tree.xpath('//div[@class="ppt_tit clearfix"]/h2/text()')[0]            download_url = a.xpath('./@href')[0]            download_data = requests.get(url=download_url,headers=headers).content            download_path = './简历模板/'+download_name+'.rar'            with open(download_path,'wb') as fp:                fp.write(download_data)                print(download_name,'success!!')

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