urlparse

>>> prourl='http://product.gongchang.com/s3946/CNS2900183019.html?gct=13.0.1-4&a=1&b=2&c=3'

>>> import urlparse

>>> import urllib

>>> urlobj=urlparse.urlparse(prourl)

>>> h=list(urlobj)

>>> h

['http', 'product.gongchang.com', '/s3946/CNS2900183019.html', '', 'gct=13.0.1-4&a=1&b=2&c=3', '']

>>> query=urlobj.query

>>> query

'gct=13.0.1-4&a=1&b=2&c=3'

>>> para_dict=dict(urlparse.parse_qsl(query))

>>> para_dict

{'a': '1', 'c': '3', 'b': '2', 'gct': '13.0.1-4'}

>>> prlist[4] = urllib.urlencode(para_dict)

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

NameError: name 'prlist' is not defined

>>> h[4] = urllib.urlencode(para_dict)

>>> h

['http', 'product.gongchang.com', '/s3946/CNS2900183019.html', '', 'a=1&c=3&b=2&gct=13.0.1-4&d=4', '']

>>> urlparse.ParseResult(*h).geturl()  

'http://product.gongchang.com/s3946/CNS2900183019.html?a=1&c=3&b=2&gct=13.0.1-4&d=4'