"Paddy" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> I have another use case.
> If you want to match a comma separated list of words you end up writing
> what constitutes a word twice, i.e:
> r"\w+[,\w+]"
> As what constitues a word gets longer, you have to repeat a longer RE
> fragment so the fact that it is a match of a comma separated list is
> lost, e.g:
> r"[a-zA-Z_]\w+[,[a-zA-Z_]\w+]"
>
> - Paddy.
>
Write a short function to return a comma separated list RE. This has the
added advantage of DRY, too. Adding an optional delim argument allows you
to generalize to lists delimited by dots, dashes, etc.
(Note - your posted re requires 2-letter words - I think you meant
"[A-Za-z_]\w*", not "[A-Za-z_]\w+".)
-- Paul
import re
def commaSeparatedList(regex, delim=","):
return "%s[%s%s]*" % (regex, delim, regex)
listOfWords = re.compile( commaSeparatedList(r"\w+") )
listOfIdents = re.compile( commaSeparatedList(r"[A-Za-z_]\w*") )
# might be more robust - people put whitespace in the darndest places!
def whitespaceTolerantCommaSeparatedList(regex, delim=","):
return r"%s[\s*%s\s*%s]*" % (regex, delim, regex)
# (BTW, delimitedList in pyparsing does this too - the default delimiter is
a comma, but other expressions can be used too)
from pyparsing import Word, delimitedList, alphas, alphanums
listOfWords = delimitedList( Word(alphas) )
listOfIdents = delimitedList( Word(alphas+"_", alphanums+"_") )
-- Paul
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