[Memphis.pm] sorts

[Carl Brock Sides]

* Keith W. Sheffield <sheff at pobox.com> [001005 23:22]:

> I though of ways to compact the sort demos given tonight and I got the
> following scripts at the end of this post.
> 
> (listing 1 is faster, BTW).

Strange, listing 2 is faster on my machine.

csides at tanuki:~/sorting$ time ./keith1.pl < ips > /dev/null

real  0m5.123s
user  0m4.990s
sys   0m0.110s
csides at tanuki:~/sorting$ time ./keith2.pl < ips > /dev/null

real  0m2.982s
user  0m2.840s
sys   0m0.120s

Using Benchmark.pm shows that the single pack is a lot more efficient
than the join/map/sprintf combo:

csides at tanuki:~/sorting$ cat benchmark.pl 
#!/usr/local/perl-5.6/bin/perl -w

use Benchmark;

timethese(100000, { 
   keith1 => 'join("", map {sprintf "%03d", $_;} split(/\./,
"192.168.0.1"))',
   keith2 => 'pack("C4", split( /\./, "192.168.0.1"))' 
});
__END__
csides at tanuki:~/sorting$ ./benchmark.pl 
Benchmark: timing 100000 iterations of keith1, keith2...
Useless use of join in void context at (eval 2) line 1.
    keith1: 20 wallclock secs (20.84 usr +  0.00 sys = 20.84 CPU) @
4798.46/s (n=100000)
Useless use of pack in void context at (eval 4) line 1.
    keith2:  6 wallclock secs ( 6.88 usr +  0.03 sys =  6.91 CPU) @
14471.78/s (n=100000)

> ---- listing 1 ----
> #!/usr/bin/perl
> {
> local $,="\n";
> print map {$_->[0]} sort {$a->[1] <=> $b->[1]} map {chomp; [ $_,  
> 	join('', map { sprintf "%03d", $_;} split(/\./)) ]; } <>;
> print "\n";
> }
> -----
> ----- listing 2 ---
> #!/usr/bin/perl
> {
> local $,="\n";
> print map {$_->[0]} sort {$a->[1] cmp $b->[1]} map {chomp; [ $_, 
> 	pack("C4", split(/\./)) ]; } <>;
> print "\n";
> }

-- 
Brock Sides
csides at autozone.com

The original plan [for GNOME] was to aim to make a desktop as good as the Macintosh, and we should not lower our ambition by making one merely as good as Windows. -- RMS 
----------------------------------------------------------------------------
To unsubscribe, please send email to majordomo at pm.org
with 'unsubscribe memphis-pm-list' in the body of the message.
----------------------------------------------------------------------------