[Tutor] RE module is working ?

[Karim]

I forget something. There is no issue with python and double quotes.
But I need to give it to TCL script but as TCL is shit string is only 
delimited by double quotes.
Thus I need to escape it to not have syntax error whith nested double 
quotes.

Regards
The poor tradesman


On 02/03/2011 12:45 PM, Karim wrote:
>
> Hello Steven,
>
> I am perhaps a poor tradesman but I have to blame my thunderbird tool 
> :-P .
> Because expression = *' "" '*  is in fact fact expression = ' "" '.
> The bold appear as stars I don't know why. I need to have escapes for 
> passing it to another language (TCL interpreter).
> So I will rewrite it not _in bold_:
>
> $ python
> Python 2.7.1rc1 (r271rc1:86455, Nov 16 2010, 21:53:40)
> [GCC 4.4.3] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
> >>> expression = ' "" '
>
> >>> re.subn(r'([^\\])?"', r'\1\\"', expression)
>
> But if I remove '?' I get the following:
>
> >>> re.subn(r'([^\\])"', r'\1\\"', expression)
> (' \\"" ', 1)
>
>     * On linux using my good old sed command, it is working with my
>       '?' (0-1 match):
>
> $ echo ' "" ' | sed 's/\([^\\]\)\?"/\1\\"/g'*
> * \"\"
>
> For me linux/unix sed utility is trusty and is the reference.
>
> Regards
> Karim
>
>
> On 02/03/2011 11:43 AM, Steven D'Aprano wrote:
>> Karim wrote:
>>>
>>> Hello,
>>>
>>> I am trying to subsitute a '""' pattern in '\"\"' namely escape 2 
>>> consecutives double quotes:
>>
>> You don't have to escape quotes. Just use the other sort of quote:
>>
>> >>> print '""'
>> ""
>>
>>
>>>    * *In Python interpreter:*
>>>
>>> $ python
>>> Python 2.7.1rc1 (r271rc1:86455, Nov 16 2010, 21:53:40)
>>> [GCC 4.4.3] on linux2
>>> Type "help", "copyright", "credits" or "license" for more information.
>>> >>> expression = *' "" '*
>>
>> No, I'm sorry, that's incorrect -- that gives a syntax error in every 
>> version of Python I know of, including version 2.7:
>>
>> >>> expression = *' "" '*
>>   File "<stdin>", line 1
>>     expression = *' "" '*
>>                  ^
>> SyntaxError: invalid syntax
>>
>>
>> So what are you really running?
>>
>>
>>
>>> >>> re.subn(*r'([^\\])?"', r'\1\\"', expression*)
>>
>> Likewise here. *r'...' is a syntax error, as is expression*)
>>
>> I don't understand what you are running or why you are getting the 
>> results you are.
>>
>>
>> > *Indeed what's the matter with RE module!?*
>>
>> There are asterisks all over your post! Where are they coming from?
>>
>> What makes you think the problem is with the RE module?
>>
>> We have a saying in English:
>>
>> "The poor tradesman blames his tools."
>>
>> Don't you think it's more likely that the problem is that you are 
>> using the module wrongly?
>>
>> I don't understand what you are trying to do, so I can't tell you how 
>> to do it. Can you give an example of what you want to start with, and 
>> what you want to end up with? NOT Python code, just literal text, 
>> like you would type into a letter.
>>
>> E.g. ABC means literally A followed by B followed by C.
>> \" means literally backslash followed by double-quote
>>
>>
>>
>>
>
>
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