From: Jeff 'japhy' Pinyan <[EMAIL PROTECTED]>
> On Feb 14, Bill Akins said:
>
> >I have a string that is read in and assigned to a veriable. String
> >looks something like this: 10.00 c$cpi c$ul (Sample Number:) c$sh
> >/Courier 0 c$fnt ( SA-01-0C8A8) c$sh ( ) c$sh /Courier 0 c$fnt
> >
> >I need the string between the second set of ()'s. There may or may
> >not be a leading space, if so, I need to strip it out. There are not
> >the exact same number of charecters in the string, the only thing
> >constant is the value I need is in the second set of ()'s.
>
> You can match it like so:
>
> my ($second_paren) = ($string =~ /\((.*?)\)/g)[1];
>
> or
>
> my ($second_paren) = ($string =~ /\(([^)]*)\)/g)[1];
#!perl
use Benchmark;
$string = '10.00 c$cpi c$ul (Sample Number:) c$sh /Courier 0 c$fnt (SA-01-0C8A8)
c$sh ( ) c$sh /Courier 0 c$fnt';
sub Japhy1 {
my $second_paren;
for(my $i=0;$i<1000;$i++) {
$second_paren = ($string =~ /\((.*?)\)/g)[1];
}
}
sub Japhy2 {
my $second_paren;
for(my $i=0;$i<1000;$i++) {
$second_paren = ($string =~ /\(([^)]*)\)/g)[1];
}
}
sub Mine1 {
my $second_paren;
for(my $i=0;$i<1000;$i++) {
$second_paren = ($string =~ /^.*?\(.*?\).*?\((.*?)\)/);
}
}
sub Mine2 {
my $second_paren;
for(my $i=0;$i<1000;$i++) {
$second_paren = ($string =~ /^[^)]*\([^)]*\)[^)]*\(([^)]*)\)/);
}
}
timethese 1000, {
Japhy1 => \&Japhy1,
Japhy2 => \&Japhy2,
Mine1 => \&Mine1,
Mine2 => \&Mine2,
}
__END__
Benchmark: timing 1000 iterations of Japhy1, Japhy2, Mine1, Mine2...
Japhy1: 14 wallclock secs (13.76 usr + 0.00 sys = 13.76 CPU) @ 72.68/s (n=1000)
Japhy2: 9 wallclock secs ( 8.95 usr + 0.00 sys = 8.95 CPU) @ 111.69/s (n=1000)
Mine1: 7 wallclock secs ( 6.25 usr + 0.00 sys = 6.25 CPU) @ 160.03/s (n=1000)
Mine2: 5 wallclock secs ( 5.03 usr + 0.00 sys = 5.03 CPU) @ 198.89/s (n=1000)
So it's better to skip explicitly the first () pair then to match all () groups and
then take
the second one. And /\([^)]*\)/ is quicker than /\(.*?\)/ (The two DO NOT mean exactly
the same!!!)
Jenda
=========== [EMAIL PROTECTED] == http://Jenda.Krynicky.cz ==========
There is a reason for living. There must be. I've seen it somewhere.
It's just that in the mess on my table ... and in my brain.
I can't find it.
--- me
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