python抓取百度首页的方法

import urllib
def downURL(url,filename):
 try:
 fp=urllib.urlopen(url)
 except:
 print('download error')
 return 0
 op=open(filename,'wb')
 while 1:
 s=fp.read()
 if not s:
 break
 op.write(s)
 fp.close()
 op.close()
 return 1
downURL("http://www.baidu.com","C:\url.txt")