Re: Configurable Matches

It's a lot easier than you might think... m// interpolates.

#!/usr/bin/perl -l

chomp($tmp = <DATA>);

$foo = 'the rain in spain';

print "match" if $foo =~ /$tmp/;

__END__

__DATA__
ain$
[download]

Change the line after __DATA__ to change the regex matched against.

--Stevie-O

$"=$,,$_=q>|\p4<6 8p<M/_|<('=>
.q>.<4-KI<l|2$<6%s!<qn#F<>;$,
.=pack'N*',"@{[unpack'C*',$_]
}"for split/</;$_=$,,y[A-Z a-z]
         {}cd;print lc
[download]

Comment on Re: Configurable Matches Select or Download Code

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Re^2: Configurable Matches by jdhawke (Acolyte) on Jun 03, 2004 at 04:41 UTC
Hmmm, this makes it even easier, any pros/cons of doing it this way vs the qr// method that Mr.Muskrat demonstrated above?	[reply]
Re^3: Configurable Matches by orderthruchaos (Scribe) on Jun 03, 2004 at 14:04 UTC
Well, you hit the pro on the head... it's much easier to interpolate variables into `m//`. There is a major con, though. If you plan on using this regular expression in a loop, it will need to be recompiled every time it is used. With `qr//`, you will only compile once... You may want to benchmark them to find out the difference: `#!/usr/bin/perl -w use Benchmark; my $txt = 'find this regex'; my $str = 'regex?'; my $rgx = qr/$str/i; timethese ( 1000000, { match => sub{ $txt =~ m/$str/i }, qreg => sub{ $txt =~ $rgx }, }, );` [download] Gives me the following: `% test.pl Benchmark: timing 1000000 iterations of match, qreg... match: 1 wallclock secs ( 0.82 usr + 0.00 sys = 0.82 CPU) @ 12 +19512.20/s (n=1000000) qreg: 0 wallclock secs ( 0.73 usr + 0.00 sys = 0.73 CPU) @ 13 +69863.01/s (n=1000000)` [download] As you can see, for a regex this simple, it doesn't matter too much... but more complicated regexs wll show a bigger difference.	[reply] [d/l] [select]