compare perl substitution against "chop if substr($var, -1) eq"

output

Benchmark: running sed, substr_if for at least 20 CPU seconds...
       sed: 21 wallclock secs (21.10 usr +  0.00 sys = 21.10 CPU) @ 1937388.20/s (n=40878891)
 substr_if: 21 wallclock secs (21.22 usr +  0.03 sys = 21.25 CPU) @ 2412531.58/s (n=51266296)
               Rate       sed substr_if
sed       1937388/s        --      -20%
substr_if 2412532/s       25%        --

substitute-vs-substr.pl

#!/usr/bin/env perl
use strict;
use warnings;
use Benchmark qw( timethese cmpthese ) ;

my $r = timethese( -20, {
        sed => sub {
                my $sed_str = "This is a sentenceL";
                $sed_str =~ s/.$//;
        },
        substr_if => sub {
                my $substr_str = "This is a sentenceL";
                chop $substr_str if (substr($substr_str, -1) eq 'L');
        },
} );
cmpthese $r;