Only using one capturing paren will improve the performance of your regex as it will not be forced to do as much backreferencing. In playing around with this, I managed to optimize the split by breaking it into a minimal number of segments. In all cases, with my example, split significantly outperformed the regex. 
#!/usr/bin/perl -w
use strict;
use Benchmark;
use vars qw($myvar $result $a $b $c $d);
$myvar = "one,two,three,four";

timethese(1000000, { 
    Regex  => '$a=$1, $b=$2, $c=$3, $d=$4 if $myvar   =~ /^[^,]+,([^,]
++),[^,]+,[^,]+$/',
    Split1 => '$result = (split /,/, $myvar)[1]',
    Split2 => '$result = (split /,/, $myvar, 4)[1]',
    Split3 => '$result = (split /,/, $myvar, 3)[1]'
});

Benchmark: timing 1000000 iterations of Regex, Split1, Split2, Split3.
+..
     Regex: 26 wallclock secs (25.75 usr +  0.00 sys = 25.75 CPU)
    Split1: 16 wallclock secs (16.31 usr +  0.00 sys = 16.31 CPU)
    Split2: 16 wallclock secs (16.15 usr +  0.00 sys = 16.15 CPU)
    Split3: 13 wallclock secs (12.74 usr +  0.00 sys = 12.74 CPU)

[download]
Note the whopping improvement in performance of Split3. In my benchmark, it's approximately twice as fast as the regex.

Cheers,
Ovid

In reply to (Ovid) RE: RE: RE: From one beginner to others . . . by Ovid
in thread From one beginner to others . . . by greenhorn

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