my @array;
        push @array, "one";
        push @array, "two";
        push @array, "three";
        psuh @array, "four";
        my $k=0;
        my @combos;
        for(combinations(@array))
        {
                $combos[$k] = join("|",@$_);
                $k++;
        }

sub combinations {
  return [] unless @_;
  my $first = shift;
  my @rest = combinations(@_);
  return @rest, map { [$first, @$_] } @rest;
}