#!/usr/bin/perl -w

use strict;
use Data::Dumper qw(Dumper);

my @keys   = qw(a b c d e f g h i j); #is longer than
my @values = qw(1 2 3 4 5);           #this..

my @array = interleave(\@keys, \@values);
print Dumper(\@array); #let's see what happens

sub interleave {
  my $array1 = shift;
  my $array2 = shift;

  my(@even, @odd);
  push @even, $_ * 2     for 0..$#$array1;
  push @odd,  $_ * 2 + 1 for 0..$#$array2;

  my @interleaved;
  @interleaved[@even, @odd] = (@$array1, @$array2);

  return wantarray ? @interleaved : \@interleaved;
}

__END__