Python RE，AttributeError：'元組'對象沒有屬性'組'

Question

我正在嘗試使用Python 2.7正則表達式來從我正在使用的課程中提供的示例網頁中檢索數據。我試圖去工作的代碼是：

email_patterns = ['(?P<lname>[\w+\.]*\w+ *)@(?P<domain> *\w+[\.\w+]*).(?P<tld>com) 

for pattern in email_patterns: 
     # 'line' is a line of text in a sample web page 
     matches = re.findall(pattern,line) 
     for m in matches: 
      print 'matches=', m 
      email = '{}@{}.{}'.format(m.group('lname'), m.group('domain'),m.group('tld')) 

運行此返回以下錯誤：

email = '{}@{}.{}'.format(m.group('lname'), m.group('domain'), m.group('tld')) 
AttributeError: 'tuple' object has no attribute 'group'. 

我想用命名的組，因爲該組的順序可以根據改變我正在匹配的文本。但是，它似乎不工作，因爲編譯器不認爲'm'是一個Group對象。

這裏發生了什麼，以及如何通過使用命名組來正確工作？

Answer 1

你有兩個問題。像Ignacio暗示的那樣，你不應該用正則表達式來解析（X）HTML ......正則表達式不能處理複雜性。另一個問題是您正在使用findall()而不是finditer()。 findall()將匹配作爲列表返回......在組發生事件時，它將其作爲元組列表返回。

finditer()另一方面返回具有group()方法的MatchGroup對象的迭代器。

從re Python文檔：

re.findall(pattern, string, flags=0) Return all non-overlapping matches of pattern in string, as a list of strings. The string is scanned left-to-right, and matches are returned in the order found. If one or more groups are present in the pattern, return a list of groups; this will be a list of tuples if the pattern has more than one group. Empty matches are included in the result unless they touch the beginning of another match.

re.finditer(pattern, string, flags=0) Return an iterator yielding MatchObject instances over all non-overlapping matches for the RE pattern in string. The string is scanned left-to-right, and matches are returned in the order found. Empty matches are included in the result unless they touch the beginning of another match.