I think it is the because sort() is very fast, and you are comparing it with an if/then (?:) control structure, which is inherantly slow.

Well, another thing to do besides benchmarking is profiling:

#!/usr/bin/perl
use strict;
use Devel::OpProf qw(profile print_stats zero_stats );
profile(1);    # turn on profiling
my $now = 8; # we'll pretend it's between 8 and 9 PM
my %url = (
       monday => {
           @{[map(($_,1), (1..1000))]}
       }
       );
#start profiling
zero_stats;
$now = (sort grep {$_ <= $now} keys %{$url{'monday'}})[-1];
print_stats;

zero_stats;
$now = ($now < $_ && $_ < 8 ? $_ : $now) for keys %{$url{'monday'}};
print_stats;
[download]

Well, this tells us a lot!

First algorithm null operation 1006 block 1001 private variable 1001 grep iterator 1000 numeric le (<=) 1000 scalar variable 1000 pushmark 7 next statement 5 glob value 3 constant item 2 subroutine entry 2 private hash 1 private array 1 sort 1 keys 1 conditional expression 1 list slice 1 hash dereference 1 hash element 1 array dereference 1 scalar assignment 1 block entry 1 grep 1

Second algorithm private variable 3000 null operation 2006 logical and (&&) 2001 glob value 1996 numeric lt (<) 1992 scalar dereference 1992 next statement 1006 conditional expression 1001 foreach loop iterator 1001 scalar assignment 1000 iteration finalizer 1000 constant item 993 pushmark 4 subroutine entry 2 block 1 keys 1 foreach loop entry 1 array dereference 1 block entry 1 private array 1 private hash 1 hash dereference 1 hash element 1 loop exit 1

So we see that just the control loop by iself takes almost as much "action" as the whole first algorithm

Paris Sinclair    |    4a75737420416e6f74686572
pariss@efn.org    |    205065726c204861636b6572
I wear my Geek Code on my finger.

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