Update: Ignore this post (mistakes pointed out by shmem and ikegami below.

Perhaps I'm doing something wrong, but my benchmarking results are radically different from shmem's.

For a start, with the same data (programme run several times), I get something like this:

           Rate splicing  radiant
splicing 2371/s       --     -19%
radiant  2936/s      24%       --
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This is not the first time that I have got very different benchmarking results than other Monks on this forum, but this time the difference is particularly egregious.

In case you're wondering:

C:\Perl\progs>perl -v
This is perl, v5.8.8 built for MSWin32-x86-multi-thread
<snip>
Binary build 817 provided by ActiveState
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And the bigger the original array gets (and the greater the number of elements to insert), the more radiantmatrix's code appears to outperform splice:

C:\Perl\progs>scratchpad.pl 6000 7000 10000
Array size: 10000
Inserting: 6000 .. 7000
           Rate splicing  radiant
splicing 28.1/s       --     -86%
radiant   198/s     603%       --
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C:\Perl\progs>scratchpad.pl 60000 61000 100000
Array size: 100000
Inserting: 60000 .. 61000
           Rate splicing  radiant
splicing 2.87/s       --     -93%
radiant  42.7/s    1388%       --
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Perhaps I've got something very very wrong, but my findings seem to be borne out by this extract from Mastering algorithms with Perl, Chapter 3:

...splicing elements into or out of the middle of a large array can be very expensive.

Here's my benchmarking code, demolish it at will:

use strict;
use warnings;
use Benchmark 'cmpthese';  

my ( $START, $END ) = @ARGV >= 2 ? @ARGV : ( 5000, 6000 );
my $SIZE = $ARGV[2] ? $ARGV[2] : 10000;

die "Bad input!\n" if $START > $END or $END > $SIZE;

my $TIMES = int 10_000_000 / $SIZE / 2;

print "Array size: $SIZE\n";
print "Inserting: $START .. $END\n";

sub insert1 {
  my ( $ra, $index, $elem ) = @_;
  @$ra = @$ra[0 ..$ index-1], $elem, @$ra[$index .. @$ra-1];
}

sub insert2 {
  my ( $ra, $index, $elem ) = @_;
  splice( @$ra, $index, 0, $elem );
}

cmpthese ( $TIMES, {
  radiant  => sub { my @ary = 1 .. $SIZE;
    insert1( \@ary, 1, $_ ) for $START .. $END },
  splicing => sub { my @ary = 1 .. $SIZE;
    insert2( \@ary, 1 ,$_ ) for $START .. $END },
} );
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