本文实例讲述了Python通过正则表达式选取callback的方法。分享给大家供大家参考。具体如下：
最近在瞎想怎么通过xpath去精确抓取文章的正文，跟parselets类似的想法，只不过更简单。
代码设计上采用正则表达式匹配URL，再选择callback handler的方式，主要参考web.py的分发器（Dispatcher)。
当然，这个实现比较老土一些，全部用function的方式回调，没有用类。
#!/bin/env python
import re, sys
# Define parser first.
def baidu(username):
# Business logic
return "Using parser Baidu. and the user's name is: %s." % username
def qzone(uin):
# Business logic
return "Using parser Qzone, and the user's QQ is: %s." % uin
# From web.py
def group(seq, size):#{{{
"""
Returns an iterator over a series of lists of length size from iterable.
>>> list(group([1,2,3,4], 2))
[[1, 2], [3, 4]]
>>> list(group([1,2,3,4,5], 2))
[[1, 2], [3, 4], [5]]
"""
def take(seq, n):
for i in xrange(n):
yield seq.next()
if not hasattr(seq, 'next'):
seq = iter(seq)
while True:
x = list(take(seq, size))
if x:
yield x
else:
break
#}}}
def parser_init(url,mapping):
for pat, what in group(mapping,2):
result = re.compile('^' + pat + '$').match(url)
if result:
return what, [x for x in result.groups()]
return None, None
if __name__ == '__main__':
mapping = (
'http://(?:hi|space).baidu.com/([^/]+)(?:/.*)?','baidu',
'http://(\d+).qzone.qq.com(?:/.*)?','qzone',
)
(func, args) = parser_init(sys.argv[1],mapping)
if func:
callback = func
if func in globals():
callback = globals()[func]
if callable(callback):
print callback(*args)
else:
print 'No parser found.';
希望本文所述对大家的Python程序设计有所帮助。
