Dynamic text color

[John Posner]

On Fri, 08 Jan 2010 14:28:57 -0500, MRAB <python at mrabarnett.plus.com>  
wrote:

> Dave McCormick wrote:
>>   On Wed, Jan 6, 2010 at 9:18 AM, John Posner <jjposner at optimum.net  
>> <mailto:jjposner at optimum.net>> wrote:
>>      On Tue, 05 Jan 2010 16:54:44 -0500, Dave McCormick
>>     <mackrackit at gmail.com <mailto:mackrackit at gmail.com>> wrote:
>>          But it is not what I am wanting. I first thought to make it  
>> look
>>         for a space but that would not work when a single character like
>>         "#" is to be colored if there is a "string" of them.  Or if all
>>         of the characters between quotes are to be colored.
>>       Regular expressions are good at handling searches like:
>>      * all the characters between quotes
>>     * the two-character string "do", but only if it's a complete word
>>      -John
>>      --     http://mail.python.org/mailman/listinfo/python-list
>>  I need another hint...
>>  Been doing some reading and playing and it looks like
>> r'\bxxx\b'
>> is what I need. But I can not figure out how to pass a variable between
>> \b___\b
>> If the word in question is between the "\b \b" and in the list then it  
>> works like I want it to.
>>  The below does not work.
>>      greenList_regexp = "|".join(greenList)
>>     for matchobj in re.finditer(r'\bgreenList_regexp\b', complete_text):
>>         start,end = matchobj.span()
>>
> The regex r'\bgreenList_regexp\b' will match the string
> 'greenList_regexp' if it's a whole word.
>
> What you mean is "any of these words, provided that they're whole
> words". You'll need to group the alternatives within "(?:...)", like
> this:
>
>      r'\b(?:' + greenList_regexp + ')\b'

Oops, MRAB, you forgot to make the last literal a RAW string -- it should  
be r')\b'

Dave, we're already into some pretty heavy regular-expression work, huh?.  
Here's another approach -- not nearly as elegant as MRAB's:

Given this list:

   greenList = ['green', 'grass', 'grump']

... you currently are using join() to construct this regexp search string:

   'green|grass|grump'

... but you've decided that you really want this similar regexp search  
string:

   r'\bgreen\b|\bgrass\b|\bgrump\b'

You can achieve this by transforming each item on the list, then invoking  
join() on the transformed list to create the search string. Here are a  
couple of ways to transform the list:

* List comprehension:

   whole_word_greenList = [ r'\b' + word + r'\b' for word in greenList]

* map() and a user-defined function:

   def xform_to_wholeword_searchstring(word):
       return r'\b' + word + r'\b'

   whole_word_greenList = map(xform_to_wholeword_searchstring, greenList)


HTH,
John