最基本的抓取网页内容的代码实现：

#!/usr/bin/env python 
 
from urllib import urlretrieve 
 
def firstNonBlank(lines): 
  for eachLine in lines: 
    if not eachLine.strip(): 
      continue 
    else: 
      return eachLine 
 
def firstLast(webpage): 
  f = open(webpage) 
  lines = f.readlines() 
  f.close() 
  print firstNonBlank(lines), 
  lines.reverse() 
  print firstNonBlank(lines), 
 
def download(url=\'http://www\',process=firstLast): 
  try: 
    retval = urlretrieve(url)[0] 
  except IOError: 
    retval = None 
  if retval: 
    process(retval) 
 
if __name__ == \'__main__\': 
  download() 

利用urllib模块，来实现一个网页中针对图片的抓取功能：

import urllib.request 
import socket 
import re 
import sys 
import os 
targetDir = r\"C:\\Users\\elqstux\\Desktop\\pic\" 
def destFile(path): 
  if not os.path.isdir(targetDir): 
    os.mkdir(targetDir) 
  pos = path.rindex(\'/\') 
  t = os.path.join(targetDir, path[pos+1:]) 
  return t 
 
if __name__ == \"__main__\": 
  hostname = \"http://www.douban.com\" 
  req = urllib.request.Request(hostname) 
  webpage = urllib.request.urlopen(req) 
  contentBytes = webpage.read() 
  for link, t in set(re.findall(r\'(http:[^\\s]*?(jpg|png|gif))\', str(contentBytes))): 
    print(link) 
    urllib.request.urlretrieve(link, destFile(link)) 

import urllib.request 
import socket 
import re 
import sys 
import os 
targetDir = r\"H:\\pic\" 
def destFile(path): 
  if not os.path.isdir(targetDir): 
    os.mkdir(targetDir) 
  pos = path.rindex(\'/\') 
  t = os.path.join(targetDir, path[pos+1:]) #会以/作为分隔 
  return t 
 
if __name__ == \"__main__\": 
  hostname = \"http://www.douban.com/\" 
  req = urllib.request.Request(hostname) 
  webpage = urllib.request.urlopen(req) 
  contentBytes = webpage.read() 
  match = re.findall(r\'(http:[^\\s]*?(jpg|png|gif))\', str(contentBytes) )#r\'(http:[^\\s]*?(jpg|png|gif))\'中包含两层圆括号，故有两个分组， 
                             #上面会返回列表，括号中匹配的内容才会出现在列表中 
  for picname, picType in match: 
    print(picname) 
    print(picType) 
    
 
\'\'\'\'\' 
输出： 
http://img3.douban.com/pics/blank.gif 
gif 
http://img3.douban.com/icon/g111328-1.jpg 
jpg 
http://img3.douban.com/pics/blank.gif 
gif 
http://img3.douban.com/icon/g197523-19.jpg 
jpg 
http://img3.douban.com/pics/blank.gif 
gif 
... 
\'\'\'