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解析

一、xpath

• 安装lxml库

pip install lxml ‐i https://pypi.douban.com/simple 

• 导入lxml.etree

from lxml import etree 

• etree.parse() 解析本地文件

html_tree = etree.parse('XX.html')

• etree.HTML() 服务器响应文件

html_tree = etree.HTML(response.read().decode('utf‐8')

• html_tree.xpath(xpath路径)

抓取站长素材图片案例

# @Author: Achang
# @Time: 2022/2/11 16:27
# @File: lxml_解析站长素材图片
# @Project: 爬虫基础

# https://sc.chinaz.com/tupian/shuaigetupian.html

import urllib.request
import lxml.etree



headers = {
    "User-Agent": 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36',
}


def create_request(page):
    if page == 1:
        url = "https://sc.chinaz.com/tupian/shuaigetupian.html"
    else:
        url = "https://sc.chinaz.com/tupian/shuaigetupian_"+str(page)+".html"

    print(url)
    requestObj = urllib.request.Request(headers=headers,url=url)
    return requestObj


def get_context(requestObj):
    context = urllib.request.urlopen(requestObj)
    result = context.read().decode('utf-8')
    return result


def down_load(context):
    tree = lxml.etree.HTML(context)
    name_list = tree.xpath("//div[@id='container']//a/img/@alt")
    pic_url_list = tree.xpath("//div[@id='container']//a/img/@src2")
    for index in range(len(name_list)):
        urllib.request.urlretrieve(url="https:"+pic_url_list[index],filename="./img/"+name_list[index]+'.jpg')


if __name__ == '__main__':
    start_page = int(input("请输入起始页"))
    end_page = int(input("请输入结束页"))

    for page in range(start_page,end_page+1):
        requestObj = create_request(page)
        context = get_context(requestObj)
        down_load(context)

二、JsonPath

• pip安装

pip install jsonpath 

• jsonpath的使用

obj = json.load(open('json文件', 'r', encoding='utf‐8'))
ret = jsonpath.jsonpath(obj, 'jsonpath语法')

• jsonpath与lxml语法对比
  
• 数据源

{ "store": {
    "book": [ 
      { "category": "reference",
        "author": "Nigel Rees",
        "title": "Sayings of the Century",
        "price": 8.95
      },
      { "category": "fiction",
        "author": "Evelyn Waugh",
        "title": "Sword of Honour",
        "price": 12.99
      },
      { "category": "fiction",
        "author": "Herman Melville",
        "title": "Moby Dick",
        "isbn": "0-553-21311-3",
        "price": 8.99
      },
      { "category": "fiction",
        "author": "J. R. R. Tolkien",
        "title": "The Lord of the Rings",
        "isbn": "0-395-19395-8",
        "price": 22.99
      }
    ],
    "bicycle": {
      "color": "red",
      "price": 19.95
    }
  }
}

• jsonpath与lxml写法对比
  

• 通过jsonpath_读取淘票票城市接口案例

import json
import jsonpath
import urllib.request

headers = {
    "User-Agent": 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36',
    'cookie': 'miid=536765677517889060; t=78466542de5dbe84715c098fa2366f87; cookie2=11c90be2b7bda713126ed897ab23e35d; v=0; _tb_token_=ee5863e335344; cna=jYeFGkfrFXoCAXPrFThalDwd; xlly_s=1; tfstk=cdlVBIX7qIdVC-V6pSNwCDgVlVEAa8mxXMa3nx9gjUzPOZeuYsAcXzbAiJwAzG2c.; l=eBxbMUncLj6r4x9hBO5aourza77T6BAb4sPzaNbMiInca6BOT3r6QNCnaDoy7dtjgtCxretPp0kihRLHR3xg5c0c07kqm0JExxvO.; isg=BHBwrClf5nUOJrpxMvRIOGsqQT7CuVQDlydQ-WrHREsaJRDPEsmVk5EbfS1FtQzb',
    'referer': 'https://dianying.taobao.com/',
    'content-type': 'text/html;charset=UTF-8'
}


def create_request():
    res_obj = urllib.request.Request(url="https://dianying.taobao.com/cityAction.json?activityId&_ksTS=1644570795658_173&jsoncallback=jsonp174&action=cityAction&n_s=new&event_submit_doGetAllRegion=true",headers=headers)
    return res_obj


def get_context(req_obj):
    resp = urllib.request.urlopen(req_obj)
    origin_context = resp.read().decode('utf-8')
    result = origin_context.split('jsonp174(')[1].split(')')[0]
    return result


def download_and_parse(context):
    with open('jsonpath_淘票票案例.json','w',encoding='utf-8') as fp:
        fp.write(context)


def parse_json():
    obj = json.load(open('jsonpath_淘票票案例.json', mode='r', encoding='utf-8'))
    region_name_list = jsonpath.jsonpath(obj, '$..regionName')
    print(region_name_list)
    print(len(region_name_list))


if __name__ == '__main__':
    req_obj = create_request()
    context = get_context(req_obj)
    download_and_parse(context)
    parse_json()

• 爬取Boss直聘城市信息

import urllib.request
import jsonpath
import json

url = 'https://www.zhipin.com/wapi/zpgeek/common/data/citysites.json'
resp = urllib.request.urlopen(url)
context = resp.read().decode('utf-8')
result = jsonpath.jsonpath(json.loads(context),'$..name')
print(result)

三、BeautifulSoup

• 基本简介
  

• 安装以及创建
  

• 节点定位
  
  

• 节点信息
  

• 爬取星巴克图片案例

  from bs4 import BeautifulSoup
  import urllib.request
  
  
  url = 'https://www.starbucks.com.cn/menu/'
  
  resp = urllib.request.urlopen(url)
  context = resp.read().decode('utf-8')
  soup = BeautifulSoup(context,'lxml')
  obj = soup.select("ul[class='grid padded-3 product'] div[class='preview circle']")
  for item in obj:
      completePicUrl = 'https://www.starbucks.com.cn'+item.attrs.get('style').split('url("')[1].split('")')[0]
      print(completePicUrl)
  

• 爬取证券之光板块信息案例

  from bs4 import BeautifulSoup
  import urllib.request
  
  
  url = 'http://quote.stockstar.com/'
  context = urllib.request.urlopen(url).read().decode('gb2312')
  soup = BeautifulSoup(context,'lxml')
  list = soup.select('#datalist2 .align_left a')
  for item in list:
      print(item.get_text())
  

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