how to right the regular expression ?

python mailtomanage at 163.com
Fri Feb 15 01:32:14 CET 2013


the regex--- pat = r'([a-z].+?\s)(.+)(?:(\(.+\)))?' ,do not work at all.


>>> rfile.close()
>>> import re
>>> rfile=open("tv.txt","r")
>>> pat1 = r'([a-z].+?\s)(.+)((\(.+\)))?'
>>> for  line in  rfile.readlines():
...     Match=re.match(pat1,line)
...     print "1group is ",Match.group(1),"2group is ",Match.group(2),"3group is ",Match.group(3)
... 
1group is  http://202.177.192.119/radio5  2group is  香港电台第五台(可于Totem/VLC/MPlayer播放) 3group is  None
1group is  http://202.177.192.119/radio35  2group is  香港电台第五台(DAB版,可于Totem/VLC/MPlayer播放) 3group is  None
1group is  http://202.177.192.119/radiopth  2group is  香港电台普通话台(可于Totem/VLC/MPlayer播放) 3group is  None
1group is  http://202.177.192.119/radio31  2group is  香港电台普通话台(DAB版,可于Totem/VLC/MPlayer播放) 3group is  None
1group is  octoshape:rthk.ch1  2group is  香港电台第一台(粤) 3group is  None
1group is  octoshape:rthk.ch2  2group is  香港电台第二台(粤) 3group is  None
1group is  octoshape:rthk.ch6  2group is  香港电台普通话台 3group is  None
1group is  octoshape:rthk.ch3  2group is  香港电台第三台(英) 3group is  None




>>> rfile.close()
>>> import re
>>> rfile=open("tv.txt","r")
>>> pat2 = r'([a-z].+?\s)(.+?)((\(.+\)))?'
>>> for  line in  rfile.readlines():
...     Match=re.match(pat1,line)
...     print "1group is ",Match.group(1),"2group is ",Match.group(2),"3group is ",Match.group(3)
... 
1group is  http://202.177.192.119/radio5  2group is  香港电台第五台(可于Totem/VLC/MPlayer播放) 3group is  None
1group is  http://202.177.192.119/radio35  2group is  香港电台第五台(DAB版,可于Totem/VLC/MPlayer播放) 3group is  None
1group is  http://202.177.192.119/radiopth  2group is  香港电台普通话台(可于Totem/VLC/MPlayer播放) 3group is  None
1group is  http://202.177.192.119/radio31  2group is  香港电台普通话台(DAB版,可于Totem/VLC/MPlayer播放) 3group is  None
1group is  octoshape:rthk.ch1  2group is  香港电台第一台(粤) 3group is  None
1group is  octoshape:rthk.ch2  2group is  香港电台第二台(粤) 3group is  None
1group is  octoshape:rthk.ch6  2group is  香港电台普通话台 3group is  None
1group is  octoshape:rthk.ch3  2group is  香港电台第三台(英) 3group is  None








在 2013-02-14 23:43:42,MRAB <python at mrabarnett.plus.com> 写道:
>On 2013-02-14 14:13, python wrote:
>> my tv.txt is :
>> http://202.177.192.119/radio5 香港电台第五台(可于Totem/VLC/MPlayer播放)
>> http://202.177.192.119/radio35 香港电台第五台(DAB版,可于Totem/VLC/MPlayer播放)
>> http://202.177.192.119/radiopth 香港电台普通话台(可于Totem/VLC/MPlayer播放)
>> http://202.177.192.119/radio31 香港电台普通话台(DAB版,可于Totem/VLC/MPlayer播放)
>> octoshape:rthk.ch1 香港电台第一台(粤)
>> octoshape:rthk.ch2 香港电台第二台(粤)
>> octoshape:rthk.ch6 香港电台普通话台
>> octoshape:rthk.ch3 香港电台第三台(英)
>>
>> what i want to get the result is
>> 1group is  http://202.177.192.119/radio5  2group is  香港电台第五台  3group is  (可于Totem/VLC/MPlayer播放)
>> 1group is  http://202.177.192.119/radio35  2group is  香港电台第五台  3group is  (DAB版,可于Totem/VLC/MPlayer播放)
>> 1group is  http://202.177.192.119/radiopth  2group is  香港电台普通话台  3group is  (可于Totem/VLC/MPlayer播放)
>> 1group is  http://202.177.192.119/radio31  2group is  香港电台普通话台  3group is  (DAB版,可于Totem/VLC/MPlayer播放)
>> 1group is  octoshape:rthk.ch1  2group is  香港电台第一台 3group is  (粤)
>> 1group is  octoshape:rthk.ch2  2group is  香港电台第二台 3group is  (粤)
>> 1group is  octoshape:rthk.ch6  2group is  香港电台普通话台 3group is  none
>> 1group is  octoshape:rthk.ch3  2group is  香港电台第三台 3group is  (英)
> >
>> here is my code:
>> # -*- coding: utf-8 -*-
>> import re
>> rfile=open("tv.txt","r")
>> pat=r'([a-z].+?\s)(.+)(\(.+\))'
>> for  line in  rfile.readlines():
>>      Match=re.match(pat,line)
>>      print "1group is ",Match.group(1),"2group is
>> ",Match.group(2),"3group is ",Match.group(3)
>> rfile.close()
>>
>> the output is :
>> 1group is  http://202.177.192.119/radio5  2group is  香港电台第五台
>> 3group is  (可于Totem/VLC/MPlayer播放)
>> 1group is  http://202.177.192.119/radio35  2group is  香港电台第五台
>> 3group is  (DAB版,可于Totem/VLC/MPlayer播放)
>> 1group is  http://202.177.192.119/radiopth  2group is  香港电台普通话台
>> 3group is  (可于Totem/VLC/MPlayer播放)
>> 1group is  http://202.177.192.119/radio31  2group is  香港电台普通话台
>> 3group is  (DAB版,可于Totem/VLC/MPlayer播放)
>> 1group is  octoshape:rthk.ch1  2group is  香港电台第一台 3group is  (粤)
>> 1group is  octoshape:rthk.ch2  2group is  香港电台第二台 3group is  (粤)
>> 1group is
>> Traceback (most recent call last):
>>    File "tv.py", line 7, in <module>
>>      print "1group is ",Match.group(1),"2group is ",Match.group(2),"3group is ",Match.group(3)
>> AttributeError: 'NoneType' object has no attribute 'group'
>>
>> how to revise my code to get the output?
>>
>The problem is that the regex makes '(\(.+\))' mandatory, but example 7
>doesn't match it.
>
>You can make it optional by wrapping it in a non-capturing group
>(?:...), like this:
>
>pat = r'([a-z].+?\s)(.+)(?:(\(.+\)))?'
>
>Also, it's highly recommended that you use raw string literals
>(r'...') when writing regex patterns and replacements.
>
>-- 
>http://mail.python.org/mailman/listinfo/python-list
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