Lxml模块

lxml： 它可以分析xml文件,html是xml的子集，所以分析html文档可以使用正则也可以使用lxml
示例文档

        
 li test3
        
          
          J K. Rowling
          2005
          29.99
          
li test1
          
li test2
        


    
li test4

lxml示例

实例1： 找到Harry Potter
/bookstore/book/title
实例： 找到book里面所有li
/bookstore/book/li
实例： 找到bookstore里面所有li
/bookstore/book/li|/bookstore/li (|表示或的意思)
/bookstore//li //表示不管层次只要是li全部找到
实例： 找到整个文档中的li
//li
实例：找到所有含有id属性的li
//li[@id]
实例：找到所有含有id属性的li,并且id的值为test3
//li[@id=‘test3’]
实例：找到所有li的id属性
//li/@id 得到标签中的属性值
//li/text() 得到标签中的内容

一个完整示例：

from lxml import etree
html = '''    
            
 li test3
            
              
              J K. Rowling
              2005
              29.99
              
li test1
              
li test2
            
    
    
        
li test4
    '''

dom = etree.HTML(html)
ret = dom.xpath('//li/text()')
print(ret)
ret = dom.xpath('//li/@id')
print(ret)

一个完整示例：

   from lxml import etree
    html = '''    
                
 li test3
                
                  
                  J K. Rowling
                  2005
                  29.99
                  
li test1
                  
li test2
                
        
        
            
li test4
        '''

    dom = etree.HTML(html)
    ret = dom.xpath('//li[@id]')
    for li in ret:
        print(li.text)
        print(li.attrib['id'])
        print(etree.tostring(li).decode())
        print('=' * 50)



  #爬取暴漫非人哉漫画
    #author : shuaijie_liu
    #date 2019-05-01
    #email : [email protected]
    import requests
    from lxml import etree
    def down_html(url,timeout=10,headers=None,verify=True):
        if not headers:
            headers = {
                'User-Agent':r'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36,'
            }
            req = requests.get(url=url,headers=headers,verify=verify,timeout=timeout)
            return req.text
    def find_imgs(data,exp):
        dom = etree.HTML(data)
        ret = dom.xpath(exp)
        return ret
    def download_img(url,filename,timeout=10,headers=None,verify=True):
        if not headers:
            headers = {
                'User-Agent':r'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36,'
            }
        req = requests.get(url=url,headers=headers,verify=verify,timeout=timeout)
        with open(filename,'wb') as f:
            f.write(req.content)
    if __name__ == '__main__':
        for page in range(27):
            url = r'http://baozoumanhua.com/channels/1562?page={}'.format(page)
            imgs = r'//div[@class="article-body"]//img/@src'
            try:
                html = down_html(url=url)
            except Exception as e:
                print('Html Error {} : {}'.format(url,e))
                continue
            img_urls = find_imgs(html,imgs)
            ret = [img_urls[0]]
            for url in img_urls:
                if url != ret[-1]: ret.append(url)
            filename = 0
            for url in ret:
                filename += 1
                file = "{}-{}.jpg".format(page+1,filename)
                print('down load {}'.format(url))
                try:
                    download_img(url,file)
                except Exception as e:
                    print('IMAGE ERROR {}:{}'.format(url,e))