python爬虫

python爬虫和node爬虫的原理是一样的，就是先请求，再换字符串，接着匹配，最后存入数据库备用

　　下面是爬虫一个当当网的

#!/usr/bin/python
# -*- coding: UTF-8 -*- 

import requests
from bs4 import BeautifulSoup
import re
import pymysql
 
 
def create():
    db = pymysql.connect("localhost", "root", "ldlx", "TESTDB")
 
    cursor = db.cursor()
    cursor.execute("DROP TABLE IF EXISTS EMPLOYER")
 
    sql = """CREATE TABLE EMPLOYER (
            ID INT PRIMARY KEY AUTO_INCREMENT,
            LOGO  CHAR(255),
            PRICE CHAR(20),
            AUTHER CHAR(255) )"""
 
    cursor.execute(sql)
 
    db.close()
 
def insert(value):
    db = pymysql.connect("localhost", "root", "ldlx", "TESTDB")
 
    cursor = db.cursor()
    sql = "INSERT INTO EMPLOYER(LOGO,PRICE,AUTHER) VALUES (%s, %s,  %s)"
    try:
        cursor.execute(sql,value)
        db.commit()
        print('插入数据成功')
    except:
        db.rollback()
        print("插入数据失败")
    db.close()
 
create()
 
#re匹配需要的数据
pertern = re.compile(
    r'<img.*?data-original="(.*?)".*?<span class="search_now_price">(.*?)</span>.*?<a.*?单品作者.*?title="(.*?)">.*?</a>',
    re.S)
#添加请求头   修改user-agent来伪装浏览器
headers={'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36'}
url = 'http://category.dangdang.com/cp01.19.34.00.00.00.html'
res = requests.get(url,headers=headers)
print(res.status_code)
soup = BeautifulSoup(res.text, 'html.parser')
data = soup.find_all('ul', attrs={'class': 'bigimg'})
data = str(data)
item = re.findall(pertern, data)
for i in item:
    print(i)
    insert(i)

执行结果如下：

 注：如果报错什么引入的module找不到就直接去python安装目录下的script文件夹下打开cmd，然后通过pip install 模块名下载即可