python简易爬虫制作

编译环境:pycharm 4.5.3

python版本:3.5.1

首先从pycharm库中下载并安装BeautifulSoup4,lxml,requests,time插件


以KnewOne为例:

from bs4 import BeautifulSoup
import requests
import time

url='https://knewone.com/things'  
web_data=requests.get(url)  #利用requests访问网页
soup=BeautifulSoup(web_data.text,'lxml') #解析网页
titles=soup.select(' section.content > h4 > a ') #网页元素定位
imgs=soup.select('a.cover-inner > img')
for title,img in zip(titles,imgs):    #少部分数据可以先用字典封装,大数据再考虑用数据库
    data={
        'title':title.get_text(),
        'img':img.get('src'),
    }
    print(data)

此外,发现KnewOne的“产品”页面为一个异步加载网页,那么,如何爬取一页所有的信息呢?

def get_info(url,data=None):
    web_data=requests.get(url)
    soup=BeautifulSoup(web_data.text,'lxml')
    titles=soup.select(' section.content > h4 > a ')
    imgs=soup.select('a.cover-inner > img')

    if(data==None):
        for title,img in zip(titles,imgs):
            data={
                'title':title.get_text(),
                'img':img.get('src'),
            }
            print(data)

def get_mor_pages(start,end):
    for one in range(start,end):
        get_info(url+str(one))


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