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。