creating an (inefficent) alternating regular expression from a list of options
Larry Bates
larry.bates at vitalEsafe.com
Tue Sep 9 09:19:04 EDT 2008
metaperl.com wrote:
> Pyparsing has a really nice feature that I want in PLY. I want to
> specify a list of strings and have them converted to a regular
> expression.
>
> A Perl module which does an aggressively optimizing job of this is
> Regexp::List -
> http://search.cpan.org/~dankogai/Regexp-Optimizer-0.15/lib/Regexp/List.pm
>
> I really dont care if the expression is optimal. So the goal is
> something like:
>
> vowel_regexp = oneOf("a aa i ii u uu".split()) # yielding r'(aa|a|uu|
> u|ii|i)'
>
> Is there a public module available for this purpose?
>
>
Perhaps I'm missing something but your function call oneOf(...) is longer than
than actually specifying the result.
You can certainly write quite easily:
def oneOf(s):
return "|".join(s.split())
-Larry
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