From: Corey Haines <coreyhaines@...>
Date: 2008-02-03T07:58:59+09:00
Subject: Re: Extracting vowels and consonants using regular expression

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Interesting. I guess you could post-process a bit on the two sets that you
get back. A regular expression that can handle the y would be good, I guess.

On Feb 2, 2008 5:40 PM, Donovan Dillon <donovan.dillon@verizon.net> wrote:

> Thanks Robert, Corey, Philip, Stephano, et. al, for all of the great
> suggestions. However, they all seem to ignore the conditional nature of
> 'y'
> as a vowel. I would like the regex to treat 'y' as a vowel when there is
> no
> other vowel either before or after it. The string I used initially, was
> drawn from the following perl code that accomplishes this (found at
> http://www.perlmonks.org/?node_id=592867):
>
>
> my @vowels = ( /[aeiou]|(?<![aeiou])y(?![aeiou])/gi );
>
> The "(?<!...)" is a "zero-width negative-look-behind assertion".
>
> The "(?!...)" is a "zero-width negative-look-ahead assertion".
>
> Together, they match the condition of treating "y as a vowel only if there
> is no other vowel before or after it."
>
>
> This was my attempt at converting the Perl fragment to Ruby syntax:
>
> scan(/[aeiou]|(?![aeiou])y(?![aeiou])/i)
>
> I have since discovered that Ruby 1.8 lacks regex look-behind assertion --
> which explains why the code was failing. As a result, I have fallen back
> to
> the following which currently ignores the 'y':
>
> class String
>  def vowels
>    scan(/[aeiou]/i)
>  end
>  def consonants
>    scan(/[^aeiou]/i)
>  end
> end
>
>
> Any ideas how to modify this to include the conditional treatment of "y as
> a
> vowel only if there is no other vowel before or after it?"
>
> (i.e., is there a way to simulate the perl "zero-width
> negative-look-behind"
> and "zero-width negative-look-ahead" assertions for 'y' in Ruby 1.8?)
>
>
> On 2/2/08 4:17 PM, in article
> 335e48a90802021417n4ba96a11i746bd5118f18464e@mail.gmail.com, "Robert
> Dober"
> <robert.dober@gmail.com> wrote:
>
> > Oh sorry using 1.9 excluseviley now...
> > Robert
> >
>
>
>


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