python抓取网页的一个小例子

#!/usr/bin/python
#coding=utf-8
from BeautifulSoup import BeautifulSoup
import urllib
import re
import time

def getHtml(url):
page = urllib.urlopen(url)
html = page.read()
return html

def check(result_list,url):
#	html = getHtml("http://stock.cnstock.com/live");
html = getHtml(url);
soup = BeautifulSoup(html);
myul=soup.find('ul',id='zb-list');

first=myul.findAll('a')[0];

result_list.append(first['href']);
result_list.append(first['title']);

html = getHtml(first['href']);
#print html;

soup = BeautifulSoup(html,fromEncoding="gb2312");

mydiv=soup.find('div',id='qmt_content_div');

#print mydiv;

for item in mydiv.findAll('a'):
result_list.append(item['href']);
result_list.append(item.getText());

#print result_list;

#print len(result_list);

result_list=[];
old_result_list=[];

while True:
check(result_list,"http://stock.cnstock.com/live");

if cmp(old_result_list,result_list):
print "changed";
for li in result_list:
print li;
else:
print "no changed";

old_result_list= result_list[:];
del result_list [:];
#time.strftime( ISOTIMEFORMAT, time.localtime( time.time() ) );
print time.ctime();#time.localtime() ;
time.sleep(5);