From: Swink, Dave (DSwink@protrader.com)
Date: Fri Feb 21 2003 - 17:42:40 GMT-3
Tim,
The problem is to match "123_(any number of characters or no characters at
all)456" or "456_(any number of characters or no characters at all)123".
The ".*" means one character or white space and 0 or more of the same, so
the "_" you added would be needed. The "?" covers the possibility that
there may not be any characters at all between 123_ and 456 by saying "the
stuff in the pararentheses or maybe nothing".
Dave Swink
-----Original Message-----
From: Tim Fletcher [mailto:tim@fletchmail.net]
Sent: Friday, February 21, 2003 2:27 PM
To: Swink, Dave; 'Cezar Fistik'; ccielab@groupstudy.com
Subject: RE: Re:
Dave,
Your absolutely right, but your solution doesn't solve the problem. "."
means any character and "*" means any number of the preceeding character or
group of characters, so applying a "?" to that group has no meaning. The
problem is that the 2 "_" would require at least 2 spaces between the 123
and 456. Also you forgot a couple of necessary "_"s (probably just a typo).
So what it should be is:
_123_(.*_)?456_|_456_(.*_)?123_
-Tim Fletcher
At 11:36 AM 2/21/2003 -0600, Swink, Dave wrote:
>Cezar,
>
>That answer matches "AS123 (any number of additional ASs) AS456" or "AS456
>(any number of additional ASs) AS123" but it does not match "AS123 AS456"
or
>"AS456 AS123". That is why it needs the ? after the .* to give it the "or
>nothing" option: _123_(.*)?_456|456_(.*)?_123
>
>Dave Swink
>
>-----Original Message-----
>From: Cezar Fistik [mailto:cfistik@moldovacc.md]
>Sent: Friday, February 21, 2003 6:28 AM
>To: ccielab@groupstudy.com
>Subject: Re: Re:
>
>
>Hi all,
>
>Just realized it is not good. The expression 123.*456 would match also
>AS1234 and/or AS3456 and so on, that is not the desired result. It also
>wouldn't match AS-PATHS when AS456 is before AS123, so here comes a little
>improvment:
>
>_123_.*_456|456_.*_123
>
>What do you think?
>
>Cezar Fistik
>
>----- Original Message -----
>From: "Cezar Fistik" <cfistik@moldovacc.md>
>To: <ccielab@groupstudy.com>
>Sent: Friday, February 21, 2003 1:23 AM
>Subject: Re:
>
>
> > Hi,
> >
> > I don't know if there si an "and" in regular expressions, never heard of
> > it. In order to match AS123 AND AS456 you can try using the following
> > expressoin:
> >
> > 123.*456
> >
> > Regards,
> > Cezar Fistik
> >
> > ----- Original Message -----
> > From: "Ram Shummoogum" <rshummoo@ca.ibm.com>
> > To: <ccielab@groupstudy.com>
> > Sent: Thursday, February 20, 2003 10:34 PM
> >
> >
> > > Hi ALL:
> > >
> > >
> > > I need some help on this BGP regular expression.
> > >
> > >
> > > Make a router only accept routes that has transit AS 123 and AS 456.
>The
> > > keyword here is "and" and not or.
> > >
> > >
> > > Ex: {34 5 6 456 7 99 123 88}
> > > {45 123 89 456 7}
> > >
> > >
> > >
> > >
> > >
> > > I know "OR" is | but what is AND.
> > >
> > >
> > >
> > >
> > >
> > > Thanks for your help
> > >
> > >
> > > RAM
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