Using 5.005_03, I got almost identical times with the following code: (41 seconds for \d{2} and 40 seconds for \d\d. But this could be a second granularity problem.) 

use strict;

speed_test('\d{2}', sub { shift() =~ /\d{2}/ });
speed_test('\d\d', sub { shift() =~ /\d\d/ });

sub speed_test {
    my ($name, $func) = @_;
    my $start = time;

    my $index = 10000000;
    while ($index-- > 0) {
        &$func($index);
    }

    my $end = time - $start;

    print "Total time for $name: $end\n";
}

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It just occured to me that the subroutine indirection might be the bottleneck, but when I wrote a new version, the times were also identical. Additionally, I tested other numbers such as \d{5} (and corresponding \d\d\d\d\d) but this had no effect on the timing either.

YMMV.

-Ted

In reply to Re: Regex optimizations by tedv
in thread Regex optimizations by Ovid

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