python爬虫基础源代码

爬取百度网页源代码：

import requests
r=requests.get("http://www.baidu.com")
r.status_code
r.encoding
r.encoding=r.apparent_encoding
r.text

结果展示：

爬取网页的通用代码框架

import requests
def getHTMLText(url):
    try:
        r=requests.get(url,timeout=30)
        r.raise_for_status()
        r.encoding=r.apparent_encoding
        return r.text
    except:
        return "产生异常"
if __name__ =="__main__":
    url="http://www.baidu.com"
    print(getHTMLText(url))

爬取结果展示

京东商品页面爬取

import requests
url="http://item.jd.com/2967929.html"
try:
    r=requests.get(url)
    r.raise_for_status()
    r.encoding=r.apparent_encoding
    print(r.text[:1000])
except:
    print("爬取失败")

爬取结果展示：

亚马逊商品爬取源代码

import requests
url="https://www.amazon.cn/gp/product/B01M8L5Z3Y"
try:
    kv={ 
   'user-agent':'Mozilla/5.0'}
    r=requests.get(url,headers=kv)
    r.raise_for_status()
    r.encoding=r.apparent_encoding
    print(r.text[1000:2000])
except:
    print("爬取失败")

结果展示:

百度搜索全代码

import requests
keyword="Python"
try:
    kv={ 
   'wd':'keyword'}
    r=requests.get("http://www.baidu.com/s",params=kv)
    print(r.request.url)
    r.raise_for_status()
    print(len(r.text))
except:
    print("爬取失败！")

结果展示：

360搜素全代码

import requests
keyword="Python"
try:
    kv={ 
   'q':keyword}
    r=requests.get("http://www.so.com/s",params=kv)
    print(r.request.url)
    r.raise_for_status()
    print(len(r.text))
except:
    print("爬取失败")

结果展示：

爬取高清图片源代码

import requests
import os
url="http://image.nationalgeographic.com.cn/2017/0211/20170211061910157.jpg"
root="D://pics//"
path=root+url.split('/')[-1]
try:
    if not os.path.exists(root):
        os.mkdir(root)
    if not os.path.exists(path):
        r=requests.get(url)
        with open(path,'wb') as f:
            f.write(r.content)
            f.close()
            print("文件保存成功")
    else:
        print("文件爬取失败")
except:
    print("爬取失败")

获取源代码

import requests
r=requests.get("http://python123.io/ws/demo.html")
r.text
demo=r.text
from bs4 import BeautifulSoup
soup=BeautifulSoup(demo,"html.parser")
print(soup.prettify())
soup.title

爬取结果显示：