Replace and inserting strings within .txt files with the use of regex

MRAB python at mrabarnett.plus.com
Mon Aug 9 17:15:03 CEST 2010


Νίκος wrote:
> On 9 Αύγ, 16:52, MRAB <pyt... at mrabarnett.plus.com> wrote:
>> Νίκος wrote:
>>> On 8 Αύγ, 17:59, Thomas Jollans <tho... at jollans.com> wrote:
>>>> Two problems here:
>>>> str.replace doesn't use regular expressions. You'll have to use the re
>>>> module to use regexps. (the re.sub function to be precise)
>>>> '.'  matches a single character. Any character, but only one.
>>>> '.*' matches as many characters as possible. This is not what you want,
>>>> since it will match everything between the *first* <? and the *last* ?>.
>>>> You want non-greedy matching.
>>>> '.*?' is the same thing, without the greed.
>>> Thanks you,
>>> So i guess this needs to be written as:
>>> src_data = re.sub( '<?(.*?)?>', '', src_data )
>> In a regex '?' is a special character, so if you want a literal '?' you
>> need to escape it. Therefore:
>>
>>      src_data = re.sub(r'<\?(.*?)\?>', '', src_data)
> 
> i see, or perhaps even this:
> 
>    src_data = re.sub(r'<?(.*?)?>', '', src_data)
> 
> maybe it works here as well.

No. That regex means that it should match:

     <?        # optional '<'
     (.*?)?    # optional group of any number of any characters
     >         # '>'



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