使用Python3编写抓取网页和只抓网页图片的脚本

#!/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() 

import urllib.request 
import socket 
import re 
import sys 
import os 
targetDir = r"C:UserselqstuxDesktoppic" 
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 
... 
'''