Python 2：

import urlparse
url = 'http://foo.appspot.com/abc?def=ghi'
parsed = urlparse.urlparse(url)
print urlparse.parse_qs(parsed.query)['def']

Python 3：

import urllib.parse as urlparse
from urllib.parse import parse_qs
url = 'http://foo.appspot.com/abc?def=ghi'
parsed = urlparse.urlparse(url)
print(parse_qs(parsed.query)['def'])

parse_qs返回值列表，因此上述代码将打印['ghi']。