Statamic v2 array batch addon idea

example-template.html

{{ collection:blog as="posts" }}

    <h3>Group 1</h3>
    {{ posts scope="tag" array_batch.split="3" array_batch.select="1" }}
        {{ partial:block }}
    {{ /posts }}

    <h3>Group 2</h3>
    {{ posts scope="tag" array_batch.split="3" array_batch.select="2" }}
        {{ partial:block }}
    {{ /posts }}

    <h3>Group 3</h3>
    {{ posts scope="tag" array_batch.split="3" array_batch.select="3" }}
        {{ partial:block }}
    {{ /posts }}

{{ /collection:blog }}

SelectModifier.php

<?php

namespace Statamic\Addons\ArrayBatch;

use Statamic\Extend\Modifier;

class SelectModifier extends Modifier
{
    /**
     * Modify a value
     *
     * @param mixed  $value    The value to be modified
     * @param array  $params   Any parameters used in the modifier
     * @param array  $context  Contextual values
     * @return mixed
     */
    public function index($value, $params, $context)
    {
        return $value[$params[0] - 1];
    }
}

SplitModifier.php

<?php

namespace Statamic\Addons\ArrayBatch;

use Statamic\Extend\Modifier;

class SplitModifier extends Modifier
{
    /**
     * Modify a value
     *
     * @param mixed  $value    The value to be modified
     * @param array  $params   Any parameters used in the modifier
     * @param array  $context  Contextual values
     * @return mixed
     */
    public function index($value, $params, $context)
    {
        return $this->split($value, $params[0]);
    }

    /**
     * Logic from a newer version of \Illuminate\Support\Collection::split()
     *
     * @param array $value
     * @param int $numberOfGroups
     * @return static
     */
    public function split($value, $numberOfGroups)
    {
        $collection = collect($value);

        if ($collection->isEmpty()) {
            return collect();
        }

        $groups = collect();

        $groupSize = floor($collection->count() / $numberOfGroups);

        $remain = $collection->count() % $numberOfGroups;

        $start = 0;

        for ($i = 0; $i < $numberOfGroups; $i++) {
            $size = $groupSize;

            if ($i < $remain) {
                $size++;
            }

            if ($size) {
                $groups->push(collect(array_slice($collection->all(), $start, $size)));

                $start += $size;
            }
        }

        return $groups;
    }
}