Re: [MacPerl] $PREMATCH Question

------=_Part_82373_1828379329.1454543349193
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit

Ronald and Matthew, many thanks. jl
 

 

 

-----Original Message-----
From: Ronald J Kimball <[email protected]>
To: Jonathan Levi <[email protected]>
Cc: macperl <[email protected]>
Sent: Wed, Feb 3, 2016 12:55 pm
Subject: Re: [MacPerl] $PREMATCH Question

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


------=_Part_82373_1828379329.1454543349193
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: 7bit

<font color='black' size='2' face='Arial, Helvetica, sans-serif'>R<font size="2">onald and Matthew, many thanks. jl</font>
<div> <br>

</div>



<div> <br>

</div>



<div> <br>

</div>



<div style="font-family:helvetica,arial;font-size:10pt;color:black">-----Original Message-----<br>

From: Ronald J Kimball &lt;[email protected]&gt;<br>

To: Jonathan Levi &lt;[email protected]&gt;<br>

Cc: macperl &lt;[email protected]&gt;<br>

Sent: Wed, Feb 3, 2016 12:55 pm<br>

Subject: Re: [MacPerl] $PREMATCH Question<br>

<br>

On Tue, Feb 02, 2016 at 08:59:44PM -0500, Jonathan Levi via macperl wrote:<br>

&gt; Can someone explain why the following:<br>

&gt; <br>

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

&gt; <br>

&gt; yields "" instead of "al", as I expected?<br>

&gt; <br>

&gt; Jonathan<br>

<br>

If you want the long name, you need to use the English module, as<br>

mentioned near the top of perlvar &lt;<a href="http://perldoc.perl.org/perlvar.html" target="_blank">http://perldoc.perl.org/perlvar.html</a>&gt;.<br>

For example:<br>

<br>

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

<br>

Using /p and ${^PREMATCH}, as Matthew suggested, will avoid performance<br>

penalties in longer scripts, however.<br>

<br>

Ronald<br>

</div>

</font>
------=_Part_82373_1828379329.1454543349193--