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Re: [MacPerl] $PREMATCH Question

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From:
Ronald J Kimball
Date:
February 3, 2016 17:55
Subject:
Re: [MacPerl] $PREMATCH Question
Message ID:
20160203175524.GA14405@ibughas.pair.com
On Tue, Feb 02, 2016 at 08:59:44PM -0500, Jonathan Levi via macperl wrote:
> Can someone explain why the following:
> 
> echo alphabet | perl -e '$_=<STDIN>; if (m/pha/){print $PREMATCH, "\n"}'
> 
> yields "" instead of "al", as I expected?
> 
> Jonathan

If you want the long name, you need to use the English module, as
mentioned near the top of perlvar <http://perldoc.perl.org/perlvar.html>.
For example:

echo alphabet | perl -MEnglish -e '$_=<STDIN>; if (m/pha/){print $PREMATCH, "\n"}'

Using /p and ${^PREMATCH}, as Matthew suggested, will avoid performance
penalties in longer scripts, however.

Ronald

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