正则的疑惑，总是抓不到！

Question

>>> str='''<td>
...                                 
...                                     
...                                     
...                                         607
...                                     
...                                 
...                             </td>
...                             <td>
...                                 
...                                     
...                                     
...                                         13
...                                     
...                                 
...                             </td>
...                             <td>
...                                 
...                                     
...                                     
...                                         2.14%
...                                     
...                                 
...                             </td>
...                             <td>
...                                 
...                                     
...                                     
...                                         6.78
...                                     
...                                 
...                             </td>
...                             <td>
...                                 
...                                     
...                                     500
...                                 
...                             </td>
...                             <td>
...                                 
...                                     
...                                     
...                                         0.52
...                                     
...                                 
...                             </td>'''
>>> s2=re.search('<td>(.*?)</td>\s*<td>*?</td>\s*<td>.*?</td>\s*<td>.*?</td>\s*<td>.*?</td>\s*<td>.*?</td>',str)
>>> s2.group(1)
Traceback (most recent call last):
  File "<input>", line 1, in <module>
AttributeError: 'NoneType' object has no attribute 'group'
>>> s2=re.search('<td>(.*?)</td>\s*<td>*?</td>\s*<td>.*?</td>\s*<td>.*?</td>\s*<td>.*?</td>\s*<td>.*?</td>',str,re.S)
>>> s2
>>> s2=re.search('<td>(.*?)</td>\s*<td>.*?</td>\s*<td>.*?</td>\s*<td>(.*?)</td>\s*<td>>*?</td>\s*<td>(.*?)</td>',str,re.S)
>>> s2
>>> s2=re.search(u'<td>(.*?)</td>\s*<td>.*?</td>\s*<td>.*?</td>\s*<td>(.*?)</td>\s*<td>>*?</td>\s*<td>(.*?)</td>',str,re.S)
>>> s2
>>> s2=re.search('<td>(.*?)</td>\s*<td>.*?</td>\s*<td>.*?</td>\s*<td>.*?</td>\s*<td>>*?</td>\s*<td>.*?</td>',str,re.S)
>>> s2
>>> s2=re.search('<td>(.*?)</td>\s*<td>.*?</td>\s*<td>.*?</td>\s*<td>.*?</td>\s*<td>*?</td>\s*<td>.*?</td>',str,re.S)
>>> s2
>>> s2

这个我明明写正确的，为啥匹配不到请高手指点，谢谢！

Answer 1

因为你有换行符 .只匹配所有非换行字符 [.\S\s]* 匹配所有