Fwd: Error in Perlfaq6

---------- Forwarded message ----------
From: Meir Michanie <[email protected]>
Date: Wed, Aug 17, 2011 at 10:53 AM
Subject: Re: Error in Perlfaq6
To: [email protected]


=A0perlfaq6 - Regular Expressions ($Revision: 1.38 $, $Date: 2005/12/31
00:54:37 $)


On Wed, Aug 17, 2011 at 10:52 AM, Meir Michanie <[email protected]> wro=
te:
> Hi Brian,
> The foreach loop should have the following line of code instead:
> if (/\b$pattern\b/i){print ; next LINE;}
>
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D
> How do I efficiently match many regular expressions at once?
>
> =A0 =A0 =A0 ( contributed by brian d foy )
>
> =A0 =A0 =A0 Avoid asking Perl to compile a regular expression every time
> you want to match it. =A0In this example, perl must recompile the
> regular expression
> =A0 =A0 =A0 for every iteration of the foreach() loop since it has no way
> to know what $pattern will be.
>
> =A0 =A0 =A0 =A0 =A0 @patterns =3D qw( foo bar baz );
>
> =A0 =A0 =A0 =A0 =A0 LINE: while( <> )
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 {
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 foreach $pattern ( @patterns =
)
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 {
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 print if /\b$pattern\b/i;
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 next LINE;
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 }
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 }
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D
>