Well here it is: Proof that you can really perform a task in multiple ways. I needed an efficient way to cut off trailing whitespace. I was pulling values from a database and the scalars all had trailing whitespace. I had mistakenly made the column type CHAR(10) when it should have been a VARCHAR. Let me just say that the details of the job make it alright to cut the whitespace instead of fixing the underlying problem

So I had three ideas (none original) to perform this task. Here is my benchmark script.

use Benchmark;
timethese (1000000, {
        'unpack' => q{  my $foo = "test    ";
                        $foo = unpack("A8",$foo); },
        'regex'  => q{  my $foo = "test    ";
                        $foo =~ s/\s+$//;},
        'xeger'  => q{  my $foo = reverse "test    ";
                        $foo =~ s/^\s+//;
                        $foo = reverse $foo;}
} );
[download]

The standard regex, the unpack function, and the reverse regex. I figured the reverse one maybe wouldn't apply because the is no .* in the match. But it is cool enough an idea to try out.

Here are my results:

Benchmark: timing 1000000 iterations of regex, unpack, xeger...
     regex:  6 wallclock secs ( 5.71 usr +  0.00 sys =  5.71 CPU) @ 17
+5131.35/s (n=1000000)
    unpack:  7 wallclock secs ( 5.91 usr +  0.00 sys =  5.91 CPU) @ 16
+9204.74/s (n=1000000)
     xeger:  9 wallclock secs ( 9.26 usr +  0.00 sys =  9.26 CPU) @ 10
+7991.36/s (n=1000000)
[download]

So it seems that the regex and the unpack are very close to the same time. Notice that this is for 1 million iterations. All methods are fast. So you can use various methods for this task!