PERL Beginners - Pattern Question: One or both, but not neither

Author

Pattern Question: One or both, but not neither

Siegfried Heintze

2005-06-03, 8:55 pm

Can I write a pattern that matches "Tampa" or "Florida", or "Tampa Florida"?

Thanks,
Siegfried

-----Original Message-----
From: Jeff 'japhy' Pinyan [mailto:japhy@perlmonk.org]
Sent: Friday, June 03, 2005 8:44 AM
To: Jay Savage
Cc: Perl Beginners List
Subject: Re: Search Pattern for Roman Numerals?

On Jun 3, Jay Savage said:

> On 6/3/05, Jeff 'japhy' Pinyan <japhy@perlmonk.org> wrote:
>
>
> This isn't going to get them all; it says to match (between word
> boundaries) "I" or "II" or any three non-newlines. So it will catch
> "I", "II", "III", and "VII". It will also catch "I" where it's a
> pronoun (assuming this is an english text file), and any three-letter
> words/constructs.

I'm sorry, that regex wasn't meant to be taken literally. I just didn't
feel the need to reproduce the alternations *again*.

> I would trysomething like this:
>
> s/\bI(?:I+|V|X)?|VI*|XI*\b//

This will get rid of the "I" in "Ishmael". Your \b anchors aren't
effective on the *entire* pattern. You're matching

\bI(?:I+|V|X)?
or
VI*
or
XI*\b

The regex I would use would probably be

/\b(?:I{1,3}|IV|VI{0,3}|I?X)\b/

--
Jeff "japhy" Pinyan % How can we ever be the sold short or
RPI Acacia Brother #734 % the cheated, we who for every service
http://japhy.perlmonk.org/ % have long ago been overpaid?
http://www.perlmonks.org/ % -- Meister Eckhart

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Chris Devers

2005-06-03, 8:55 pm

On Fri, 3 Jun 2005, Siegfried Heintze wrote:

> Can I write a pattern that matches "Tampa" or "Florida", or "Tampa Florida"?

I'm sure someone can.

What happened when you tried it?

You did try, right?

--
Chris Devers

Wagner, David --- Senior Programmer Analyst --- WG

2005-06-03, 8:55 pm

Siegfried Heintze wrote:
> Can I write a pattern that matches "Tampa" or "Florida", or "Tampa
> Florida"?=20
>=20
> Thanks,
> Siegfried
You would have to order it so that if wanted Tampa Florida that would have=
priority over Tampa or Florida

/(Tampa Florida|Tampa|Florida)/
one method.
Wags ;)

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Jeremy Vinding

2005-06-03, 8:55 pm

Wagner, David --- Senior Programmer Analyst --- WGO wrote:

>Siegfried Heintze wrote:
>
>
> You would have to order it so that if wanted Tampa Florida that would have priority over Tampa or Florida
>
> /(Tampa Florida|Tampa|Florida)/
>one method.
>Wags ;)
>
>
you could also do:
/(?:Tampa? Florida)|Tampa/

--jjv

Jeremy Vinding

2005-06-06, 3:56 pm

Ing. Branislav Gerzo wrote:

>Jeremy Vinding [JV], on Friday, June 03, 2005 at 16:34 (-0600) has on
>mind:
>
>
>
>JV> You caught me, but that matches "Tampa Tampa" too
>JV> what I really meant was:
>JV> /(?:(?:Tampa )?Florida)|Tampa/
>
>sorry, but it won't match "tampa tampa", just try :)
>it match left side from | or right side. not both :)
>So you save one (?:)
>
>(see that smile at the end:)
>
>
>
$ perl -le'print "yes" if "Tampa Tampa" =~ /(?:Tampa )?Florida|Tampa/'
yes

Jeremy Vinding

2005-06-06, 3:56 pm

Jeremy Vinding wrote:

> Ing. Branislav Gerzo wrote:
>
> $ perl -le'print "yes" if "Tampa Tampa" =~ /(?:Tampa )?Florida|Tampa/'
> yes
>
my bad, it seems to have to do w/ anchors, the second part of the
alternation was matching.

$perl -le'print "yes" if "Tampa Tampa" =~ /^(?:(?:Tampa )?Florida|Tampa)$/'

--jjv

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