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

...

'''

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