PHP utils

array_utils.php

<?php

namespace ArrayUtils;

/**
 * deep get
 *
 * @param array      $array
 * @param string|int ...$keys
 *
 * @return array|mixed
 */
function dig(array $array, ...$keys)
{
    foreach ($keys as $key) {
        $array = $array[$key];
    }
    return $array;
}

/**
 * deep set
 *
 * @param array      $array
 * @param mixed      $value
 * @param string|int ...$keys
 *
 * @return bool set or not
 */
function bury(array &$array, $value, ...$keys): bool
{
    if (empty($keys)) {
        return false;
    }

    $last = array_pop($keys);
    foreach ($keys as $key) {
        $array =& $array[$key];
    }
    $array[$last] = $value;
    return true;
}

/**
 * split an array into 2 arrays
 *
 * @param array $array
 * @param int   $index
 *
 * @return array[] [array, array]
 */
function splitAt(array $array, int $index): array
{
    $first = array_slice($array, 0, $index);
    $last = array_slice($array, $index);
    return [$first, $last];
}

array_utils_test.php

<?php

require 'array_utils.php';

use function \ArrayUtils\dig, \ArrayUtils\bury;

$a0 = [0, [1, 2]];
assert(2 === dig($a0, 1, 1));

$set = bury($a0, 'foo', 1, 0);
assert($set);
assert('foo' === dig($a0, 1, 0));

iter_utils.php

<?php

namespace IterUtils;

/**
 * @param int $start
 * @param int $limit
 * @param int $step
 *
 * @return \Generator
 */
function xrange(int $start, int $limit, int $step = 1): \Generator
{
    for ($i = $start; $i <= $limit; $i += $step) {
        yield $i;
    }
}

function take(int $n, \Iterator $iterator): \Generator
{
    while($n > 0 && $iterator->valid()) {
        yield $iterator->current();
        $iterator->next();
        --$n;
    }
}

/**
 * @see http://blog.kevingomez.fr/2016/02/26/efficiently-creating-data-chunks-in-php/
 *
 * @param \Iterator $iterable
 * @param int       $size
 *
 * @return \Generator
 */
function chunk(\Iterator $iterable, int $size): \Generator
{
    if (!($size > 0)) {
        throw new \InvalidArgumentException('Size must be positive');
    }

    while ($iterable->valid()) {
        yield take($size, $iterable);
    }
}

iter_utils_test.php

<?php

require 'iter_utils.php';

use function \IterUtils\xrange;
use function \IterUtils\chunk;

$expected = [
    [
        [0, 0, 0],
        [0, 1, 1],
        [0, 2, 2],
    ],
    [
        [1, 0, 3],
        [1, 1, 4],
        [1, 2, 5],
    ],
    [
        [2, 0, 6],
        [2, 1, 7],
        [2, 2, 8],
    ],
];

$iters = chunk(xrange(0, 8), 3);

$actual = [];

foreach ($iters as $i => $iter) {
    $ns = [];
    foreach ($iter as $j => $n) {
        $ns []= [$i, $j, $n];
    }
    $actual []= $ns;
}

assert($expected === $actual);

TODO

• zip iter
• refactor