数据解析、正则解析、bs4解析、定位标签的操作、xpath解析、爬PM2.5历史数据、爬三国片、爬糗事百科、爬药业、爬视频、爬免费建立模板

- 数据解析
    - 数据解析的作用：
        - 可以帮助我们实现聚焦爬虫
    - 数据解析的实现方式：
        - 正则
        - bs4
        - xpath
        - pyquery
     - 数据解析的通用原理
         - 问题1:聚焦爬虫爬取的数据是存储在哪里的？
             - 都被存储在了相关的标签之中and相关标签的属性中
         - 1.定位标签
         - 2.取文本或者取属性

import requests
headers = {
    'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36'
}

#如何爬取图片
url = 'https://pic.qiushibaike.com/system/pictures/12223/122231866/medium/IZ3H2HQN8W52V135.jpg'
img_data = requests.get(url,headers=headers).content #byte类型数据
with open('./img.jpg','wb') as fp:
    fp.write(img_data)

#弊端：不能使用UA伪装
from urllib import request
url = 'https://pic.qiushibaike.com/system/pictures/12223/122231866/medium/IZ3H2HQN8W52V135.jpg'
request.urlretrieve(url,filename='./qiutu.jpg')

#糗图爬取1-3页所有的图片（requests和正则的写法）
#1.使用通用爬虫将前3页对应的页面源码数据进行爬取
#通用的url模板(不可变)
dirName = './imgLibs'
if not os.path.exists(dirName):
    os.mkdir(dirName)
url = 'https://www.qiushibaike.com/pic/page/%d/'
for page in range(1,4):
    new_url = format(url%page)
    page_text = requests.get(new_url,headers=headers).text #每一个页码对应的页面源码数据
    #在通用爬虫的基础上实现聚焦爬虫（每一个页码对应页面源码数据中解析出图片地址）
    ex = '<div class="thumb">.*?<img src="(.*?)" alt.*?</div>'
    img_src_list = re.findall(ex,page_text,re.S)
    for src in img_src_list:
        src = 'https:'+src
        img_name = src.split('/')[-1]
        img_path = dirName+'/'+img_name #./imgLibs/xxxx.jpg
        request.urlretrieve(src,filename=img_path)
        print(img_name,'下载成功！！！')

- bs4解析
    - bs4解析的原理：
        - 实例化一个BeautifulSoup的对象，需要将即将被解析的页面源码数据加载到该对象中
        - 调用BeautifulSoup对象中的相关方法和属性进行标签定位和数据提取
    - 环境的安装：
        - pip install bs4
        - pip install lxml
    - BeautifulSoup的实例化：
        - BeautifulSoup(fp,'lxml'):将本地存储的一个html文档中的数据加载到实例化好的BeautifulSoup对象中
        - BeautifulSoup(page_text,'lxml'):将从互联网上获取的页面源码数据加载到实例化好的BeautifulSoup对象中

- 定位标签的操作：
    - soup.tagName：定位到第一个出现的tagName标签
    - 属性定位：soup.find('tagName',attrName='value')
    - 属性定位:soup.find_all('tagName',attrName='value'),返回值为列表
    - 选择器定位：soup.select('选择器')
        - 层级选择器：>表示一个层级  空格表示多个层级
- 取文本
    - .string:获取直系的文本内容
    - .text:获取所有的文本内容
- 取属性
    - tagName['attrName']

from bs4 import BeautifulSoup

fp = open('./test.html', 'r', encoding='utf-8')
soup = BeautifulSoup(fp, 'lxml')
soup.div  #定位到第一个出现的div标签
soup.find('div', class_='song')  #class_就是类名
soup.find('a', id="feng")  #标签和id组合
soup.find_all('div', class_="song")
soup.select('#feng')  #井号表示id
soup.select('.tang > ul > li')  # > 表示一个层级
soup.select('.tang li')  # 空格表示对个层级
a_tag = soup.select('#feng')[0]
a_tag.text
div = soup.div
div.string
div = soup.find('div', class_="song")
div.string
a_tag = soup.select('#feng')[0]
a_tag['href']

#爬取三国整篇内容（章节名称+章节内容）http://www.shicimingju.com/book/sanguoyanyi.html
fp = open('sanguo.txt','w',encoding='utf-8')
main_url = 'http://www.shicimingju.com/book/sanguoyanyi.html'
page_text = requests.get(main_url,headers=headers).text
#解析出章节名称和章节详情页的url
soup = BeautifulSoup(page_text,'lxml')
a_list = soup.select('.book-mulu > ul > li > a') #返回的列表中存储的是一个个a标签
for a in a_list:
    title = a.string
    detail_url = 'http://www.shicimingju.com'+a['href']
    detail_page_text = requests.get(detail_url,headers=headers).text
    #解析详情页中的章节内容
    soup = BeautifulSoup(detail_page_text,'lxml')
    content = soup.find('div',class_='chapter_content').text
    fp.write(title+':'+content+'\n')
    print(title,'下载成功！')
fp.close()

- xpath解析
    - xpath解析的实现原理
        - 1.实例化一个etree的对象，然后将即将被解析的页面源码加载到改对象中
        - 2.使用etree对象中的xpath方法结合着不同形式的xpath表达式实现标签定位和数据提取
    - 环境安装：
        - pip install lxml
    - etree对象的实例化：
        - etree.parse('test.html')
        - etree.HTML(page_text)

- xpath表达式:xpath方法的返回值一定是一个列表
    - 最左侧的/表示：xpath表达式一定要从根标签逐层进行标签查找和定位
    - 最左侧的//表示：xpath表达式可以从任意位置定位标签
    - 非最左侧的/:表示一个层级
    - 非最左侧的//：表示夸多个层级
    - 属性定位：//tagName[@attrName="value"]
    - 索引定位：//tagName[index] 索引是从1开始
- 取文本：
    - /text():直系文本内容
    - //text():所有的文本内容
- 取属性：
    - /@attrName

from lxml import etree
tree = etree.parse('./test.html')
tree.xpath('/html/head/title')
tree.xpath('//title')
tree.xpath('/html/body//p')
tree.xpath('//p')
tree.xpath('//div[@class="song"]')
tree.xpath('//li[7]')
tree.xpath('//a[@id="feng"]/text()')[0]
tree.xpath('//div[@class="song"]//text()')
tree.xpath('//a[@id="feng"]/@href')

# 爬取糗百中的段子内容和作者名称（xpath的写法）
url = 'https://www.qiushibaike.com/text/'
page_text = requests.get(url, headers=headers).text

# 解析内容
tree = etree.HTML(page_text)
div_list = tree.xpath('//div[@id="content-left"]/div')
for div in div_list:
    author = div.xpath('./div[1]/a[2]/h2/text()')[0]  # 实现局部解析
    content = div.xpath('./a[1]/div/span//text()')
    content = ''.join(content)

    print(author, content)

#http://pic.netbian.com/4kmeinv/中文乱码的处理  
dirName = './meinvLibs'
if not os.path.exists(dirName):
    os.mkdir(dirName)
url = 'http://pic.netbian.com/4kmeinv/index_%d.html'
for page in range(1,11):
    if page == 1:
        new_url = 'http://pic.netbian.com/4kmeinv/' 
    else:
        new_url = format(url%page)
    page_text = requests.get(new_url,headers=headers).text
    tree = etree.HTML(page_text)
    a_list = tree.xpath('//div[@class="slist"]/ul/li/a')
    for a in a_list:
        img_src = 'http://pic.netbian.com'+a.xpath('./img/@src')[0]
        img_name = a.xpath('./b/text()')[0]
        img_name = img_name.encode('iso-8859-1').decode('gbk')
        img_data = requests.get(img_src,headers=headers).content
        imgPath = dirName+'/'+img_name+'.jpg'
        with open(imgPath,'wb') as fp:
            fp.write(img_data)
            print(img_name,'下载成功！！！')

#https://www.aqistudy.cn/historydata/所有城市名称
page_text = requests.get('https://www.aqistudy.cn/historydata/',headers=headers).text
tree = etree.HTML(page_text)
# hot_cities = tree.xpath('//div[@class="bottom"]/ul/li/a/text()')
# all_cities = tree.xpath('//div[@class="bottom"]/ul/div[2]/li/a/text()')
cities = tree.xpath('//div[@class="bottom"]/ul/div[2]/li/a/text() | //div[@class="bottom"]/ul/li/a/text()') #提高xpath的通用性
cities

url = "https://www.aqistudy.cn/historydata/"
page_text = requests.get(url).text
tree = etree.HTML(page_text)
hot_cities = tree.xpath("//div[@class='bottom']/ul/li/a/text()")  # 热门城市
all_cities = tree.xpath("//div[@class='bottom']/ul/div[2]/li/a/text()")  # 全部城市
cities = tree.xpath("//div[@class='bottom']/ul/div[2]/li/a/text() | //div[@class='bottom']/ul/li/a/text()")  # 热门城市和全部城市
# /html/body/div[1]/div/div[1]/a/img    # copy的xpath
print(cities)

爬PM2.5历史数据.py（xpath的写法）

import requests
from lxml import etree

url = "https://www.aqistudy.cn/historydata/"
page_text = requests.get(url).text
tree = etree.HTML(page_text)
hot_cities = tree.xpath("//div[@class='bottom']/ul/li/a/text()")  # 热门城市
all_cities = tree.xpath("//div[@class='bottom']/ul/div[2]/li/a/text()")  # 全部城市
cities = tree.xpath("//div[@class='bottom']/ul/div[2]/li/a/text() | //div[@class='bottom']/ul/li/a/text()")  # 热门城市和全部城市
# /html/body/div[1]/div/div[1]/a/img    # copy的xpath
print(cities)

爬三国片.py（bs4的写法）

import requests
from bs4 import BeautifulSoup

fp = open("sanguo1.txt", "w", encoding="utf-8")
url = "http://www.shicimingju.com/book/sanguoyanyi.html"
page_text = requests.get(url).text
soup = BeautifulSoup(page_text, "lxml")
a_list = soup.select(".book-mulu > ul > li > a")
for a in a_list:
    title = a.string
    detail_url = "http://www.shicimingju.com" + a["href"]
    detail_page_text = requests.get(detail_url).text
    soup = BeautifulSoup(detail_page_text, "lxml")
    content = soup.find("div", class_="chapter_content").text
    fp.write(title + ":" + content + "\n")
    print(title, "下载成功")
fp.close()

爬糗事百科.py（requests和正则写法）

import os
import re
import requests
from urllib import request

dirName = './imgLibs'
if not os.path.exists(dirName):
    os.mkdir(dirName)
url = 'https://www.qiushibaike.com/pic/page/%d/'
headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36'
}
for page in range(1, 4):
    new_url = format(url % page)
    page_text = requests.get(new_url, headers=headers).text  # 每一个页码对应的页面源码数据
    # 在通用爬虫的基础上实现聚焦爬虫（每一个页码对应页面源码数据中解析出图片地址）
    ex = '<div class="thumb">.*?<img src="(.*?)" alt.*?</div>'
    img_src_list = re.findall(ex, page_text, re.S)
    for src in img_src_list:
        src = 'https:' + src
        img_name = src.split('/')[-1]
        img_path = dirName + '/' + img_name  # ./imgLibs/xxxx.jpg
        request.urlretrieve(src, filename=img_path)
        print(img_name, '下载成功！！！')

爬药业.py（requests的写法）

import requests

headers = {
    "User-Agent": "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36"
}
url = "http://125.35.6.84:81/xk/itownet/portalAction.do?method=getXkzsList"
for page in range(1, 6):
    print("正在爬取第{}页数据:".format(page))
    data = {
        "on": "true",
        "page": str(page),
        "pageSize": "15",
        "productName": "",
        "conditionType": "1",
        "applyname": "",
        "applysn": "",
    }
    company_data = requests.post(url, headers=headers, data=data).json()
    for dic in company_data["list"]:
        _id = dic["ID"]
        detail_url = "http://125.35.6.84:81/xk/itownet/portalAction.do?method=getXkzsById"
        data = {
            "id": _id
        }
        detail_data = requests.post(url=detail_url, data=data, headers=headers).json()
        print(detail_data)
        # print(detail_data["businessPerson"], detail_data["certStr"])

爬视频.py（硬爬）

import requests
import os
from lxml import etree

print("正在爬取")
response = requests.get(
    "http://www.lening100.com:80//uploads//mp4/%E5%85%B4%E8%B6%A3%E7%88%B1%E5%A5%BD/%E5%9B%BD%E5%AD%A6/G5002%E6%98%93%E7%BB%8F%E7%9A%84%E6%99%BA%E6%85%A7I_%E6%9B%BE%E4%BB%95%E5%BC%BA/G500201%E6%98%93%E7%BB%8F%E7%9A%84%E6%99%BA%E6%85%A7I01.mp4")
print(response)
with open("视频.mp4", "wb") as f:
    f.write(response.content)
print("爬取结束")

爬免费建立模板.py

import requests
import os
import time
import random
from bs4 import BeautifulSoup
from urllib import request
from lxml import etree

dirName = './免费简历模板'
if not os.path.exists(dirName):
    os.mkdir(dirName)
url = "http://sc.chinaz.com/jianli/free_%d.html"
for page in range(1, 8):
    try:
        if page == 1:
            new_url = "http://sc.chinaz.com/jianli/free.html"
        else:
            new_url = format(url % page)
        response = requests.get(new_url)
        response.encoding = "utf-8"
        soup = BeautifulSoup(response.text, "html.parser")
        id_obj = soup.find(name="div", attrs={"id": "container"})
        list_div = id_obj.find_all(name="div")
        share = 1
        for div in list_div:
            a = div.find(name="a")
            a_href = a.get("href")
            img = a.find(name="img")
            alt_name = img.get("alt")
            href_response = requests.get(a_href)
            href_response.encoding = "utf-8"
            tree = etree.HTML(href_response.text)
            li_list = tree.xpath('//*[@id="down"]/div[2]/ul/li[1]')
            for a in li_list:
                jl_href = a.xpath("./a/@href")[0]
                jl_path = dirName + "/" + alt_name + ".zip"
                request.urlretrieve(jl_href, filename=jl_path)
                print(jl_href, alt_name, "下载成功！")
    except Exception as e:
        pass