a bb c
d e f
g h

##</code><code>##

use strict;
use warnings;

sub chunk_array {
    my ($n, @vals) = @_;
    my $str;
    my $i = 0;
    for my $v (@vals) {
        ++$i;
        $str .= $v . ( ($i % $n) ? " " : "\n" );
    }
    substr($str, -1, 1) = "\n";
    return $str;
}

my $v1 = chunk_array(3, "a", "bb", "c", "d", "e", "f", "g", "h");
$v1 eq "a bb c\nd e f\ng h\n" or die "error: '$v1'\n";
print $v1;

my $v2 = chunk_array(3, "a", "bb", "c", "d", "e", "f");
$v2 eq "a bb c\nd e f\n" or die "error: '$v2'\n";
print $v2;

##</code><code>##

use List::MoreUtils qw(part natatime);

sub chunk_array {
    my ($n, @vals) = @_;
    my $str;
    my $iter = natatime($n, @vals);
    while ( my @line = $iter->() ) {
        $str .= join(" ", @line) . "\n";
    }
    return $str;
}

sub chunk_array {
    my ($n, @vals) = @_;
    my $i = 0;
    return join "", map { join(" ", @$_)."\n" } part { $i++/$n } @vals;
}

##</code><code>##

from itertools import *

def group(n, iterable):
  args = [iter(iterable)] * n
  return izip_longest(*args)

def chunk_array(n, vals):
  return "".join(" ".join(x for x in i if x!=None)+"\n" for i in group(n, vals))