From: George Lunsford <george.lunsford@...>
Date: 2005-11-22T02:00:34+09:00
Subject: Re: Regular Expressions and Ruby

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Right, but technically, say for "prese" that string is periodic, and should
be matched as [p][re][se] but it's not getting that last e.

On 11/21/05, Jon Lim <snowblink@gmail.com> wrote:
>
> It is matching [pr] and [es]
>
> On 21/11/05, Dirk Meijer <hawkman.gelooft@gmail.com> wrote:
> > hi,
> > i'm not entirely sure, but i'd say it's because S appears before Se (in
> your
> > regexp), so you'd have to start with all elements that have two
> letters.. i
> > think that will work, not sure though..
> > greetings, Dirk.
> >
> > 2005/11/21, George Lunsford <george.lunsford@gmail.com>:
> > >
> > > Hi, I'm new to the list and I hope this is the right place to ask the
> > > question, but I recently started learning ruby and I was writing a
> short
> > > little program to test if a word was made up of symbols from the
> periodic
> > > table. I figured I'd use ruby's built-in regex support, so I ended up
> > > writing a regex that looks something like this:
> > > (element1|element2|element3...|elementx)+
> > > Basically it's just got all 115 or so of the elements in there, and
> it's
> > > testing for one or more, right? Unfortunately this doesn't seem to
> work
> > > properly as a (nonsense) word like "presenti" should be periodic
> according
> > > to my list of elements, [p][re][se][n][ti]. Now, I can duplicate this
> > > behavior with the regex coach oddly enough. The problem seems to be
> that
> > > it
> > > parses [p][re][s] instead of [se]. I'm wondering if anyone can explai=
n
> > > this
> > > behavior to me, as I'm new to both regexps and ruby and the only rege=
x
> > > experience I've had previous to this is in some theory classes.
> Thanks.
> > > The
> > > full expression is below.
> > >
> > >
> > >
> (He|Li|Be|C|O|Ne|Na|Mg|Al|Si|S|Cl|Ar|Ca|Sc|Ti|Cr|Mn|Fe|Co|Ni|Cu|Zn|Ga|Ge|=
As|Se|Br|Kr|Rb|Sr|Zr|Nb|Mo|Tc|Ru|Rh|Pd|Ag|Cd|In|Sn|Sb|Te|Xe|Cs|Ba|Hf|Ta|Re|=
Os|Ir|Pt|Au|Hg|Tl|Pb|Bi|Po|At|Rn|Fr|Ra|Rf|Db|Sg|Bh|Hs|Mt|Uun|Uuu|Uub|Uuq|Uu=
h|Uuo|Ds|La|Ce|Pr|Nd|Pm|Sm|Eu|Gd|Tb|Dy|Ho|Er|Tm|Yb|Lu|Ac|Th|Pa|Np|Pu|Am|Cm|=
Bk|Cf|Es|Fm|Md|No|Lr|H|B|N|F|P|V|Y|I|W|Uaal)+
> > >
> > >
> >
> >
>
>
> --
> http://www.snowblink.co.uk/
>
>

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