John Posner wrote:
On Fri, 08 Jan 2010 14:28:57 -0500, MRAB <pyt...@mrabarnett.plus.com>
wrote:
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
John,
That second "r" appears to do the trick.
Yea, pretty heavy into it. I read someplace that regular-expressions
were tricky, but I did not expect this :)
Now to start working this into the rest of my app and study your second
approach.
Thanks again for the help!!!
Dave
--
http://mail.python.org/mailman/listinfo/python-list
