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.
use vars qw($myvar $result $a $b $c $d);
$myvar = "one,two,three,four";
Regex => '$a=$1, $b=$2, $c=$3, $d=$4 if $myvar =~ /^[^,]+,([^,]
Split1 => '$result = (split /,/, $myvar)',
Split2 => '$result = (split /,/, $myvar, 4)',
Split3 => '$result = (split /,/, $myvar, 3)'
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)
Note the whopping improvement in performance of Split3. In my benchmark, it's approximately twice as fast as the regex.
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