in reply to extracting variables from regex

I don't think so, apart from the famous (infamous?) $`, $&, and $', the variables which should not be named (or used).

But if you recast your regex slightly, you can get SOME information.

With a quantifier, a capturing paren shows the last element matched. But by adding another set of parens AROUND the quantifier, you can get the "grouped match". 

/(\d\.?){1,4}/ # $1 is last octet matched
/((\d\.?){1,4})/ # $1 is IP address, $2 is last octet matched

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(Edit:You're better off using the other approaches suggested in the other responses, though)

Not really useful in this case, I admit, but then again, for your academic case all you really needed was a call to split :) 

echo 1234.45.67.890 | perl -ne'printf "%X%X%X%X",split /\./'

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(Edit:Juerd is right, I should have used the split in list context)
--
Mike

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Re: Re: extracting variables from regex
by Juerd (Abbot) on Apr 02, 2002 at 22:05 UTC

    echo 1234.45.67.890 | perl -ne'split /\./; printf "%X%X%X%X",@_'

    From split's documentation:

    In scalar context, returns the number of fields found and splits into the @_ array. Use of split in scalar context is deprecated, however, because it clobbers your subroutine arguments.
    Why not have split in list context, and forget about @_?
    printf "...", split /\./

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    U28geW91IGNhbiBhbGwgcm90MTMgY
W5kIHBhY2soKS4gQnV0IGRvIHlvdS
ByZWNvZ25pc2UgQmFzZTY0IHdoZW4
geW91IHNlZSBpdD8gIC0tIEp1ZXJk

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[d/l]
      Why have split at all?
        
      echo 192.168.0.1 | perl -nle 'printf "%02X"x4, /\d+/g'

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         MeowChow                                   
               s aamecha.s a..a\u$&owag.print
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[d/l]
      Because... No particular reason :)

      I always do that for one liners, out of laziness.

      For any real script, I use -w and strict, and have gotten out of the bad habit.

      You're right, I shouldn't be doing it in one-liners, either.
      --
      Mike

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