From: Gennady Bystritsky <Gennady.Bystritsky@...>
Date: 2006-01-17T16:47:58+09:00
Subject: Re: Question about regular expression

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^ means from the beginning of a line ($ - end of line).
* means that a preceding character or group  may be repeated 0 or more =
times.

Gennady.


-----Original Message-----
From: Eric Luo [mailto:eric.wenbl@gmail.com]
Sent: Mon 1/16/2006 23:17
To: ruby-talk ML
Subject: Re: Question about regular expression
=20
Thanks very much, I really appreatiate your help

It does work, but I couldn't figure out what the ^ and * do? could you
explain that in more detail?

Thanks


2006/1/17, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov>:
>
> On Tue, 17 Jan 2006, Eric Luo wrote:
>
> > Thanks for your replay.
> >
> > To make the problem clear.
> > I want to only change the regular expression, but not the code to
> implement
> > this function.
> > Actually, the regular expression comes from a configurable table. =
I'll
> be
> > supposed to only have the privilege to update the table.
> >
> > So What I really want is a alternative way to in place of the =
regular
> > expression
> > (?<!STR )SNPB
>
>    harp:~ > cat a.rb
>    strings =3D "STR SNPB", "STR", "SNPB"
>
>    re =3D %r/^ (?: (?:[^S]) | (?:S[^T]) | (?:ST[^R]) )* SNPB /ox
>
>    strings.each do |string|
>      permutations =3D string, "foo #{ string }", "#{ string } bar", =
"foo #{
> string } bar"
>      permutations.each do |permutation|
>        puts "<#{ permutation }> matches" if re.match permutation
>      end
>    end
>
>    harp:~ > ruby a.rb
>    <SNPB> matches
>    <foo SNPB> matches
>    <SNPB bar> matches
>    <foo SNPB bar> matches
>
> hth.
>
> -a
> --
> strong and healthy, who thinks of sickness until it strikes like
> lightning?
> preoccupied with the world, who thinks of death, until it arrives like
> thunder?  -- milarepa
>
>
>


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