xpath爬虫

xpath是什么

xpath是在XML文档中搜索内容的一门语言

html是xml的一个子集

具体实现

主要依靠lxml类中的etree
demo代码
用法1、XML

from lxml import etree  xml = """  
<book>  <id>1</id>    <name>        <nick id="10086">2112</nick>        <nick id="10010">4555</nick>        <nick class="joy">fgbgn</nick>        <nick class="jolin">goog</nick>        <dir>            <nick class="ksj">gogofff</nick>            <dir>                <nick class="ksj">ggogo</nick>            </dir>        </dir>    </name></book>  
"""  tree=etree.XML(xml)  # rer = tree.xpath("/book") /表示层级  
#  
# rerr= tree.xpath("/book/id") /表示层级  
#  
# result = tree.xpath("/book/id/text()")  /输出id层级的内容 test()拿文本  
# result = tree.xpath("/book/name/nick/text()") #输出nick里的所有内容  
# result = tree.xpath("/book/name/dir/nick/text()") #输出dir中nick的内容  
# result = tree.xpath("/book/name//nick/text()") #输出name节点中的所有节点中所有的nick节点的内容，//后代  
result = tree.xpath("/book/name/*/nick/text()") # *匹配任意节点，只匹配一层  print(result)

用法2、parse

from lxml import etree  tree =etree.parse("b.html")  result = tree.xpath("/html/a[@href='dabao']/text()") #从html中a里面的href=dapao的数据  result = tree.xpath("/html/@href")  #输出html中href中的数据 比如dapao  ol_li_list=tree.xpath("/html/a")  for li in ol_li_list:  result=li.xpath("./o/text()") #查找html/a/o/中的结果  result2=li.xpath("./o/@href") #查找/html/a/o/中href=xxx的内容

用法3、HTML

newstart

import requests  
from lxml import etree  
url ='http://eci-2zedc18yc0kv02b4wfp5.cloudeci1.ichunqiu.com/start'  
url1='http://eci-2zedc18yc0kv02b4wfp5.cloudeci1.ichunqiu.com/submit'  
s=requests.session()  
a=s.get(url).content  
tree=etree.HTML(a)  
titles = tree.xpath('//p/text()')  
result = "".join(titles)  
data={  "user_input":{result}  
}  
d=s.post(url1,data=data)  
print(d.text)

几行就没了，比re和bs4都快，但是可能没有re灵活

爬取blog信息练手

本来应该爬猪八戒网的，但是现在搞了个二次认证，不太好爬取

蹭蹭blog(以得到同意，不要模仿)

import requests  
from lxml import etree  url = 'https://noobxiaomeng.top/'  rspons = requests.get(url)  rel=rspons.content  tree =etree.HTML(rel)  rell=tree.xpath("//div/h6/text()") #查找个人信息  for i in rell:  print(i)  relll=tree.xpath("//header/a[@class='post-title']/text()") #爬取文章标题  rellll=tree.xpath("//header/a[@class='post-title']/@href") #爬取文章链接  for i,j in zip(relll,rellll):  print(i+":"+j+'\n')

与bs4爬取图库对比

bs4:

import requests  
from bs4 import BeautifulSoup  url = "https://www.umei.cc/bizhitupian/weimeibizhi/"  
resp = requests.get(url=url)  
resp.encoding = 'utf-8'  
re = BeautifulSoup(resp.text,"html.parser")  
ac = re.find("div",class_="Clbc_r_cont").find_all("a")  
for a in ac:  href = a.get("href")  print(href)  url2 = "https://www.umei.cc/"+href  page_re = requests.get(url2)  page_re.encoding = 'utf-8'  page_text = page_re.text  page = BeautifulSoup(page_text,"html.parser")  p=page.find("div",class_="big-pic")  img = p.find("img")  src = img.get("src")  #下载  img_re = requests.get(src)  img_re.content  img_name = src.split("/")[-1]  with open(img_name,mode="wb") as f:  f.write(img_re.content)  #图片保存  print("ob")  
print("over")

import requests  
from lxml import etree  url = 'https://www.umei.cc/katongdongman/dongmanbizhi/index_2.htm' #不存在1，1就不要添加后面的index，所以从2开始，多页面也可以进行遍历，没搞了  
re1=requests.get(url).content  
tree1 = etree.HTML(re1)  
tll=tree1.xpath('//div[@class="btns"]/a/@href') #读取页面链接  
for i in tll:  url2 ="https://www.umei.cc"+i  re2=requests.get(url2).content  tree2=etree.HTML(re2)  tlll = tree2.xpath('//div[@class="big-pic"]//img/@title') #匹配标题  tllll = tree2.xpath('//div[@class="big-pic"]//img/@src') #匹配链接  img_name = "".join(tlll)+'.jpg'  url3 = "".join(tllll)  img_re = requests.get(url=url3)  img_re.content  with open(img_name, mode="wb") as f:  f.write(img_re.content)  # 图片保存  print("ob")  
print('over')

可以发现比bs4简单